Test Preparation Guides

Clinical Chemistry

Lipid Profile

Test Preparation Guide — for patients and healthcare providers

1. Overview of Lipid Profile Testing

A Lipid Profile (also called a Lipid Panel or Lipid Screen) is a blood test that measures the levels of fats and fat-like substances in the blood. It is one of the most commonly requested tests for assessing cardiovascular health and screening for dyslipidemia. The test is typically used to evaluate a patient’s risk for coronary artery disease, atherosclerosis, stroke, and other conditions related to abnormal cholesterol and triglyceride levels.

2. What the Lipid Profile Measures

A standard Lipid Profile includes the following analytes:

3. Patient Preparation Instructions

Proper preparation is essential for accurate and reliable Lipid Profile results. Failure to follow these instructions may lead to false results and may require repeat testing.

3.1 Fasting Requirement

3.2 Permitted During Fasting

• Plain water — encouraged to stay well-hydrated
• Prescribed maintenance medications with a small sip of water (consult your physician first)

3.3 Not Permitted During Fasting

3.4 Medications

Do NOT stop taking prescribed medications without the guidance of your physician. Inform the laboratory staff and your doctor about all medications you are currently taking, including over-the-counter drugs, vitamins, and herbal supplements. Some medications (e.g., statins, fibrates, niacin, corticosteroids, beta-blockers) may affect lipid levels.

3.5 Diet and Lifestyle (Days Before the Test)

• Avoid unusually high-fat or high-cholesterol meals for at least 24 hours prior to the test.
• Avoid alcohol consumption for at least 24 hours before blood collection, as alcohol significantly raises triglyceride levels.
• Avoid strenuous physical exercise for at least 24 hours before the test, as vigorous activity may temporarily affect lipid values.
• Avoid smoking for at least 30 minutes before blood collection.

3.6 Other Considerations

• Inform the laboratory if you have a recent illness, fever, or infection, as acute illness may temporarily lower cholesterol levels.
• Inform the laboratory if you are pregnant, as pregnancy significantly affects lipid levels.
• For female patients: note the phase of your menstrual cycle, as hormone fluctuations can mildly affect lipid values.
• Avoid blood collection within 3 months of a myocardial infarction (heart attack) or major surgery for accurate baseline readings.

4. Blood Collection Procedure

Blood is collected via standard venipuncture, typically from the antecubital vein of the arm. The procedure takes approximately 5–10 minutes.

5. Reference Ranges and Interpretation

The following reference ranges are based on the 2018 AHA/ACC Guideline on the Management of Blood Cholesterol and the NCEP ATP III guidelines. Results should always be interpreted in the clinical context by your attending physician.

Note: Reference ranges may vary slightly depending on the analyzer, reagent system, and patient population. Results must be correlated with the patient’s clinical history, symptoms, and other laboratory findings. Final interpretation should be made by the attending physician.

6. Factors That May Affect Results

The following conditions or behaviors may cause falsely elevated or falsely lowered lipid values:

7. Frequently Asked Questions (FAQs)

This guide is intended for informational purposes only and does not constitute medical advice. Always consult your physician for clinical interpretation of results.

Clinical Chemistry

Diabetes Panel

Test Preparation Guide — for patients and healthcare providers

1. Overview of Diabetes Panel Testing

The Diabetes Panel is a group of blood tests used to screen for, diagnose, and monitor diabetes mellitus (DM) and prediabetes. Early detection and regular monitoring of blood glucose levels are essential to prevent serious complications such as neuropathy, nephropathy, retinopathy, and cardiovascular disease.

MACE Diagnostic Center offers the following tests under the Diabetes Panel:

Each test has different preparation requirements. Please read the instructions for your specific test carefully.

2. Fasting Blood Sugar (FBS)

2.1 What Is It?

The Fasting Blood Sugar (FBS) test measures the glucose level in your blood after an overnight fast. It is the most commonly used test for the initial screening and diagnosis of diabetes and prediabetes.

2.2 Preparation Instructions

Permitted During Fasting

• Plain water (encouraged — stay well hydrated)
• Prescribed medications with a small sip of water (consult your physician)

Not Permitted During Fasting

Medications

• Do NOT stop taking prescribed medications without physician guidance.
• Inform the laboratory of all medications being taken, as some drugs (e.g., corticosteroids, thiazide diuretics, beta-blockers, antipsychotics) can affect blood glucose levels.
• Insulin-dependent diabetics should follow their physician’s specific instructions regarding insulin administration before testing.

Other Notes

• Avoid strenuous physical activity for at least 8 hours before testing.
• Avoid smoking for at least 30 minutes before blood collection.
• Inform the laboratory if you are ill, febrile, or have been under significant physical stress, as these conditions affect glucose levels.

2.3 Reference Ranges (Based on ADA 2024 Guidelines)

IFG = Impaired Fasting Glucose. Note: A single elevated result is not sufficient for a diabetes diagnosis. Confirmation with a repeat FBS, HbA1c, or OGTT is required.

2.4 Factors That May Affect Results

3. Random Blood Sugar (RBS)

3.1 What Is It?

The Random Blood Sugar (RBS) test measures blood glucose at any time of day, regardless of the last meal. It is used for rapid screening, monitoring of known diabetics, and in symptomatic patients where immediate testing is required.

3.2 Preparation Instructions

Inform the Laboratory Of

• The time and content of your last meal
• All medications currently being taken
• Any insulin injections or oral hypoglycemic agents taken that day
• Whether you are experiencing symptoms (polyuria, polydipsia, fatigue, blurred vision) at the time of collection

3.3 Reference Ranges

* A random glucose of ≥ 200 mg/dL WITH classic symptoms of hyperglycemia (excessive thirst, frequent urination, unexplained weight loss) is diagnostic of diabetes mellitus per ADA guidelines.

3.4 When Is RBS Ordered?

• Urgent assessment of symptomatic patients
• Routine monitoring of known diabetics
• Post-meal glucose monitoring (2-hour postprandial glucose)
• Pre-operative glucose screening
• When FBS scheduling is not possible

4. Glycated Hemoglobin (HbA1c)

4.1 What Is It?

The HbA1c test measures the percentage of hemoglobin in red blood cells that has become attached (glycated) to glucose over approximately the past 2 to 3 months. It reflects long-term average blood glucose control and is used for both diagnosis and monitoring of diabetes mellitus.

Because red blood cells live approximately 90–120 days, HbA1c provides a picture of average glucose levels over that period — unlike FBS or RBS, which reflect glucose only at the moment of collection.

4.2 Preparation Instructions

Important Information to Disclose

Inform the laboratory of the following conditions, as they can significantly affect HbA1c accuracy:

• Recent blood transfusion (within the past 3 months) — may falsely lower HbA1c by diluting older glycated cells with new non-glycated cells.
• Hemolytic anemia or other hemolytic conditions — shorter RBC lifespan causes falsely low HbA1c.
• Iron deficiency anemia — may cause falsely elevated HbA1c.
• Hemoglobin variants or hemoglobinopathies (e.g., Sickle Cell Disease, Thalassemia, HbC disease) — may interfere with HPLC or immunoassay methods depending on the analyzer used.
• Erythropoietin (EPO) therapy or chronic kidney disease — may lower HbA1c.
• Pregnancy — HbA1c may be falsely lowered due to increased RBC turnover.
• Liver disease or splenomegaly — may affect erythrocyte lifespan.

Note: In conditions where HbA1c is unreliable, the physician may order alternative markers such as Fructosamine or Glycated Albumin.

4.3 Reference Ranges (ADA 2024)

Estimated Average Glucose (eAG) Conversion

Formula: eAG (mg/dL) = (28.7 × HbA1c) − 46.7

4.4 How Often Is HbA1c Monitored?

• Well-controlled diabetics on stable therapy: every 6 months
• Poorly controlled or newly diagnosed diabetics: every 3 months
• Patients on medication adjustment: as directed by physician

5. Oral Glucose Tolerance Test (OGTT) — For Pregnant Women (Gestational Diabetes Screening)

5.1 What Is It?

The Oral Glucose Tolerance Test (OGTT) evaluates how the body processes glucose over a period of time after drinking a standardized glucose solution. It is the gold standard for diagnosing Gestational Diabetes Mellitus (GDM) and is routinely recommended for pregnant women.

Types of OGTT:

• 75-g OGTT (2-hour): WHO and Philippine OGTT standard for GDM diagnosis; used by most Philippine health centers and DOH protocols.
• 100-g OGTT (3-hour): Alternative used in some centers (Carpenter-Coustan or NDDG criteria).

MACE Diagnostic Center performs the 75-g 2-hour OGTT unless otherwise specified by the requesting physician.

5.2 Who Should Have an OGTT?

OGTT is routinely recommended for:

• All pregnant women at 24–28 weeks of gestation (standard GDM screening)
• Pregnant women with risk factors, tested as early as the first trimester:
  • Pre-pregnancy BMI ≥ 25 (overweight) or ≥ 30 (obese)
  • Previous GDM in a prior pregnancy
  • Previous delivery of a macrosomic infant (birth weight > 4 kg)
  • Family history of Type 2 diabetes (first-degree relative)
  • Polycystic Ovary Syndrome (PCOS)
  • Unexplained previous stillbirth
  • Hypertension or cardiovascular disease

5.3 Preparation Instructions — Important: Please Read Carefully

Days Before the Test (3 days prior)

• Maintain your normal diet. Do NOT start any low-carbohydrate or restrictive diet before the test, as this can falsely lower glucose response.
• Eat a diet containing at least 150 grams of carbohydrates per day for 3 days before the test (rice, bread, pasta, fruits are acceptable).
• Avoid unusually strenuous physical activity during the 3-day period.

The Evening Before the Test

• Have a normal dinner. Your last meal should be complete by 8:00 PM to 10:00 PM (depending on your scheduled appointment time).
• After your last meal, consume NOTHING except plain water.

On the Day of the Test

• Do NOT eat any food, candy, gum, or mints from your last meal until all blood samples are collected (total duration of approximately 2–3 hours).
• You may drink plain water throughout the test. Staying hydrated is encouraged and will not affect results.
• Arrive at the laboratory at your scheduled appointment time.
• Wear comfortable clothing. You will be required to remain at the laboratory for the full duration of the test.

Medications

• Discuss with your physician which medications to take or skip on the day of the test, especially insulin and oral hypoglycemic agents.
• Certain medications such as corticosteroids, progesterone supplements, and some antiemetics can affect glucose metabolism.
• Inform the laboratory staff of ALL medications including prenatal vitamins and supplements.

5.4 Step-by-Step OGTT Procedure

1. Arrive at laboratory (T = 0:00)Inform reception that you are scheduled for an OGTT. Present your laboratory request form. Confirm fasting duration with the laboratory staff.
2. Fasting blood draw (T = 0:00)A baseline fasting blood sample is collected via venipuncture. This is your FASTING glucose (FBS) value.
3. Glucose load administration (T = 0:00 to 0:05)You will be given a glucose solution to drink — 75-g OGTT: 75 grams of anhydrous glucose dissolved in 250–300 mL water; 100-g OGTT: 100 grams of glucose in 400 mL water (if ordered). Drink the entire solution within 5 minutes. Inform staff if you feel nauseous. Do not induce vomiting — this will require rescheduling of the test.
4. Waiting period (T = 0:05 to 2:00)Remain seated or resting at the laboratory. Do NOT walk around excessively, exercise, or leave the premises. You may read, rest quietly, or use your phone while waiting. Do NOT eat, drink (except plain water), or smoke during this period.
5. 1-hour blood draw (T = 1:00) — for 100-g OGTT onlyA blood sample is drawn exactly 1 hour after the glucose load. For 75-g OGTT: this draw is skipped.
6. 2-hour blood draw (T = 2:00)A blood sample is drawn exactly 2 hours after the glucose load. This is the final sample for the 75-g OGTT.
7. 3-hour blood draw (T = 3:00) — for 100-g OGTT onlyA blood sample is drawn exactly 3 hours after the glucose load.
8. Test completeAfter the final blood draw, you may eat and resume normal activities. Results will be released approximately 1 hour after the last draw, or as indicated by the laboratory.

5.5 Diagnostic Criteria for Gestational Diabetes Mellitus (GDM)

75-g OGTT — WHO / IADPSG Criteria (used by Philippine DOH and most centers)

Diagnosis: ONE or more abnormal values = Gestational Diabetes Mellitus (GDM)

100-g OGTT — Carpenter-Coustan Criteria (alternative)

Diagnosis: TWO or more abnormal values = Gestational Diabetes Mellitus (GDM)

Non-Pregnant Adults — Standard 75-g OGTT (WHO Criteria)

Impaired Glucose Tolerance (Prediabetes): 2-hour value 140–199 mg/dL.

5.6 Important Notes for Pregnant Patients

• Always inform the laboratory of your gestational age and expected delivery date.
• If you experience severe nausea and vomiting during the test, notify the laboratory staff immediately. The test may need to be rescheduled.
• Bring a small snack (to eat after the test is completed) and a companion if needed, as the test takes 2–3 hours.
• Wear comfortable, loose clothing and bring a light jacket if needed, as the waiting area may be air-conditioned.
• If you have a prior diagnosis of GDM or are insulin-dependent, follow your physician’s specific instructions before and during the test.
• Results indicating GDM will be communicated to your referring obstetrician for appropriate clinical management.

5.7 What Happens If OGTT Is Positive?

A positive OGTT result (meeting GDM diagnostic criteria) requires:

• Referral to your obstetrician-gynecologist for GDM management
• Medical nutrition therapy (MNT) with a registered nutritionist-dietitian
• Self-monitoring of blood glucose (SMBG) at home
• Possible insulin therapy if dietary modification is insufficient
• Increased maternal-fetal surveillance during the remainder of pregnancy

GDM that is properly managed significantly reduces the risk of:

• Macrosomia (large baby / difficulty in delivery)
• Neonatal hypoglycemia
• Pre-eclampsia
• Cesarean delivery
• Development of Type 2 DM after pregnancy

6. Quick Comparison: Which Test Is for Me?

Test Selection Guide

• Are you pregnant (24–28 weeks)? → OGTT (75-g or as ordered by your OB-GYN)
• Are you a known diabetic checking long-term control? → HbA1c (every 3–6 months as advised)
• Do you have symptoms (excessive thirst, frequent urination, weight loss)? → RBS (immediate) + FBS (confirmatory)
• Are you screening for diabetes with no current symptoms? → FBS (standard first-line screen)
• Has your doctor requested confirmation of a suspected diabetes diagnosis? → FBS on two separate days OR FBS + HbA1c as advised

7. General Factors Affecting Diabetes Panel Results

8. Frequently Asked Questions (FAQs)

This guide is for informational purposes only and does not constitute medical advice. Clinical interpretation of all results must be performed by the attending physician. Reference ranges and diagnostic criteria are based on ADA 2024, WHO, and IADPSG guidelines and are subject to change as clinical evidence evolves.

Clinical Chemistry

Kidney Profile

Test Preparation Guide — Blood Urea Nitrogen (BUN), Uric Acid, Creatinine

1. Overview

The Kidney Profile (also called a Renal Function Test or RFT) is a group of blood tests that assess how well the kidneys are filtering waste products from the blood. The kidneys regulate fluid balance, electrolytes, blood pressure, and the elimination of metabolic waste. Abnormal results may indicate acute or chronic kidney disease, dehydration, gout, or other conditions.

Tests Included

2. Patient Preparation

Diet (24–48 hours before)

• Avoid high-protein meals (red meat, organ meats, large servings of fish or poultry) for at least 24 hours before testing, as protein increases BUN production.
• Avoid purine-rich foods (organ meats, sardines, anchovies, shellfish, beer, spinach, asparagus) for at least 24 hours before testing, as purines are metabolized into uric acid.
• Maintain adequate hydration. Dehydration can falsely elevate both creatinine and BUN.

Physical Activity

• Avoid strenuous or vigorous physical exercise for at least 24 hours before testing. Intense exercise increases muscle breakdown and can temporarily raise creatinine levels.

Medications

Inform the laboratory of all medications being taken. The following are known to affect kidney profile values. Do NOT stop prescribed medications without physician guidance.

Other

• Inform the laboratory if you have had recent vigorous exercise, surgery, or are on a high-protein diet or parenteral nutrition.
• Inform the laboratory if you are taking creatine supplements, as these are converted to creatinine and can falsely elevate results.

3. Reference Ranges

Blood Urea Nitrogen (BUN)

Creatinine

BUN / Creatinine Ratio (Interpretation Guide)

Uric Acid

eGFR (Estimated Glomerular Filtration Rate) — CKD Staging

4. Factors Affecting Results

This guide is for informational purposes only and does not constitute medical advice. Clinical interpretation of all results must be performed by the attending physician. Reference ranges may vary depending on the analyzer, reagent system, and patient population.

Clinical Chemistry

Liver Profile

Test Preparation Guide — AST/SGOT, ALT/SGPT, ALP, Bilirubins, Albumin, Total Protein, Globulin, A/G Ratio

1. Overview

The Liver Profile (also called Liver Function Tests / LFTs or Hepatic Panel) is a group of blood tests that evaluate the liver’s synthetic, metabolic, and excretory functions. These tests are used to detect liver damage, inflammation, obstruction of the bile ducts, and cirrhosis, and to monitor patients on hepatotoxic medications.

Tests Included

2. Patient Preparation

Diet (24–48 hours before)

• Avoid fatty, fried, and high-fat meals for at least 24 hours before testing. Fat intake stimulates bile production and can transiently affect ALP and bilirubin.
• Avoid alcohol for at least 48 hours before testing. Alcohol is directly hepatotoxic and significantly elevates AST, ALT, and GGT even in non-alcoholic individuals with a single heavy drinking episode.

Physical Activity

• Avoid strenuous exercise for at least 24 hours before testing. Vigorous activity can cause muscle breakdown that elevates AST, which is also found in skeletal muscle.

Medications

Many drugs are hepatotoxic and will affect liver enzyme results. Inform the laboratory of all medications, supplements, and herbal preparations. Do NOT stop prescribed medications without physician guidance. Key offenders include:

Other

• Inform the laboratory if you are pregnant, as ALP is physiologically elevated in pregnancy (placental isoform).
• Inform the laboratory if you have had recent vigorous physical activity, intramuscular injections, or muscle trauma, as these elevate AST.

3. Reference Ranges

Liver Enzymes

Bilirubin

Proteins

AST/ALT Ratio Interpretation

4. Factors Affecting Results

This guide is for informational purposes only and does not constitute medical advice. Clinical interpretation of all results must be performed by the attending physician. Reference ranges may vary depending on the analyzer, reagent system, and patient population.

Clinical Chemistry

Electrolytes

Test Preparation Guide — Sodium, Potassium, Chloride, Ionized Calcium, Magnesium

1. Overview

Electrolytes are electrically charged minerals dissolved in the blood and body fluids that regulate fluid balance, nerve conduction, muscle function, and acid-base homeostasis. Electrolyte imbalances can result in life-threatening cardiac arrhythmias, seizures, muscle weakness, and altered mental status. Electrolyte testing is ordered for patients with kidney disease, heart disease, hypertension, fluid imbalances, or on diuretics and IV fluids.

Tests Included

2. Patient Preparation

Specimen Collection Precautions (Critical)

Ionized Calcium

• Ionized calcium is pH-dependent. Results must be interpreted alongside the patient’s current blood pH.
• Hyperventilation before or during collection (due to anxiety) can cause respiratory alkalosis, which LOWERS ionized calcium and may cause symptoms (tingling, tetany) even with a normal total calcium.
• Breathe normally and calmly during and before blood collection.

Medications

Inform the laboratory of all current medications, as many directly affect electrolyte levels:

Other

• Inform the laboratory if you are receiving IV fluids, blood transfusions, or TPN (total parenteral nutrition), as these directly alter electrolyte levels.
• Inform the laboratory of any history of diarrhea, vomiting, or significant fluid loss prior to testing.

3. Reference Ranges

Note: Critical values are flagged immediately to the requesting physician or laboratory staff for urgent clinical action.

Clinical Implications

4. Factors Affecting Results

This guide is for informational purposes only and does not constitute medical advice. Clinical interpretation of all results must be performed by the attending physician. Reference ranges may vary depending on the analyzer, reagent system, and patient population.

Clinical Chemistry

Iron Panel

Test Preparation Guide — Serum Iron, UIBC, TIBC, Ferritin

1. Overview

The Iron Panel evaluates the body’s iron stores, iron-carrying capacity, and iron availability for red blood cell production. It is used to diagnose and differentiate types of anemia (iron deficiency anemia vs. anemia of chronic disease), iron overload conditions (hemochromatosis), and to monitor iron replacement therapy.

Tests Included

2. Patient Preparation

Other Medications Affecting the Iron Panel

Recent Blood Transfusion

• Inform the laboratory if you have received a blood transfusion within the past 4 months, as this will affect iron stores and ferritin levels.

Other

• Inform the laboratory of any recent illness or infection, as ferritin is an acute-phase reactant and will be elevated even with iron deficiency in the presence of acute inflammation or infection. This can mask iron deficiency anemia.

3. Reference Ranges

Serum Iron

UIBC, TIBC, Transferrin Saturation

Ferritin

Pattern Interpretation

4. Factors Affecting Results

This guide is for informational purposes only and does not constitute medical advice. Clinical interpretation of all results must be performed by the attending physician. Reference ranges may vary depending on the analyzer, reagent system, and patient population.

Clinical Chemistry

Amylase, LDH & Phosphorus

Test Preparation Guide — Amylase, Lactate Dehydrogenase (LDH), Phosphorus (Inorganic Phosphate)

1. Amylase

What is it? Amylase is an enzyme produced primarily by the pancreas and salivary glands that breaks down carbohydrates (starch) in digestion. Serum amylase is elevated in acute pancreatitis, salivary gland disease (parotitis), and other conditions affecting these organs. It is used as a first-line diagnostic test when acute pancreatitis is suspected.

Patient Preparation

• Fasting: Fast for at least 4 to 8 hours before collection. Avoid high-carbohydrate or high-fat meals for 24 hours before testing, as they stimulate pancreatic secretion and may mildly elevate amylase.
• Alcohol: Avoid alcohol for at least 24 hours before testing. Alcohol is a common trigger of acute pancreatitis and directly elevates amylase. Chronic alcohol use elevates amylase even in the absence of acute pancreatitis.
• Medications to disclose: Opioids/morphine (cause sphincter of Oddi spasm), thiazide diuretics, oral contraceptives, corticosteroids, valproic acid, azathioprine, furosemide, and cholinergic agents may elevate serum amylase.
• Other: Inform the laboratory if you have had recent abdominal surgery, ERCP, or trauma to the abdomen, as these can transiently elevate amylase. Note that amylase rises within 2–12 hours of acute pancreatitis onset and normalizes within 3–5 days. Lipase is preferred for later detection (ordered separately if clinically indicated).

Reference Ranges

Note: Serum amylase > 3 times the upper limit of normal (> 375 U/L) in a symptomatic patient is highly suggestive of acute pancreatitis. However, amylase may be normal in chronic pancreatitis (burned-out exocrine function) and in hypertriglyceridemia-induced pancreatitis.

2. Lactate Dehydrogenase (LDH)

What is it? Lactate Dehydrogenase (LDH) is an intracellular enzyme found in nearly all body tissues, including the heart, liver, muscles, kidneys, lungs, and red blood cells. It is released into the bloodstream whenever cells are damaged or destroyed. LDH is a nonspecific but sensitive marker of tissue injury and is used in oncology (tumor marker/monitoring), hemolysis, pulmonary embolism, and myocardial injury assessment.

LDH isoenzymes (LDH-1 through LDH-5) can be used to identify which organ or tissue is involved if clinically indicated.

Patient Preparation

• Fasting: Fast for at least 4 to 8 hours before collection. Plain water is permitted throughout the fasting period.
• Physical activity: Avoid strenuous physical exercise for at least 24 hours before collection. Vigorous activity causes muscle cell breakdown and substantially elevates LDH (skeletal muscle isoform LDH-5).

Medications to Disclose

• Anesthetics, aspirin, narcotics, procainamide, fluorides — may elevate LDH
• Clofibrate — may lower LDH
• Oxalate, fluoride anticoagulants in the collection tube — inhibit LDH activity (use only plain serum tubes unless otherwise specified)

Reference Ranges

Clinical Conditions Associated With Elevated LDH

• Hemolytic anemia (very high LDH-1, LDH-2)
• Myocardial infarction (LDH-1 predominant, but troponin now preferred)
• Liver disease, hepatitis, cirrhosis (LDH-5)
• Pulmonary embolism (LDH-3)
• Malignancies — lymphoma, leukemia, solid tumors (tumor monitoring)
• Megaloblastic anemia (B12/folate deficiency)
• Muscular dystrophy, rhabdomyolysis (LDH-5)
• Renal infarction (LDH-1, LDH-2)
• COVID-19 severity monitoring

3. Phosphorus (Inorganic Phosphate)

What is it? Serum Phosphorus (also reported as Inorganic Phosphate or PO₄) measures the level of phosphate in the blood. Phosphorus is the second most abundant mineral in the body after calcium and is critical for bone formation, energy metabolism (ATP), and acid-base regulation. Serum phosphorus is regulated by the kidneys, parathyroid hormone (PTH), and vitamin D. It is commonly ordered alongside calcium, kidney function tests, and parathyroid hormone levels.

Diet (the Day Before)

• Avoid unusually high phosphorus-containing foods for 24 hours before testing. High-phosphorus foods include: dairy products (milk, cheese, yogurt), processed foods with phosphate additives, carbonated soft drinks (especially colas), organ meats, nuts, seeds, and whole grains.
• Avoid alcohol for at least 24 hours before testing, as alcohol promotes renal phosphate excretion and can lower serum phosphorus.

Medications to Disclose

Specimen Handling

• Separate serum from cells promptly. Red blood cells contain high intracellular phosphate; delayed processing causes phosphate to leak out of cells and falsely elevate results.
• Avoid hemolysis for the same reason.

Other

• Inform the laboratory if you are receiving phosphate binders, dialysis, IV nutrition (TPN), or antacid therapy.
• Inform the laboratory of any history of parathyroid disease, kidney disease, or vitamin D deficiency.

Reference Ranges

Note: Reference ranges differ for children, in whom phosphorus is normally higher due to active bone growth (neonates up to 8.0 mg/dL; children 4.0–7.0 mg/dL). Inform the laboratory if testing a pediatric patient.

Clinical Conditions Associated With Abnormal Phosphorus

This guide is for informational purposes only and does not constitute medical advice. Clinical interpretation of all results must be performed by the attending physician. Reference ranges may vary depending on the analyzer, reagent system, and patient population.

Clinical Chemistry

Quick Reference & Reminders

All chemistry panels at a glance · general reminders for all tests

1. All Panels at a Glance

2. General Reminders for All Tests

1. Always present your laboratory request form from your physician at the reception desk before blood collection.
2. Inform the laboratory of ALL medications, supplements, herbal preparations, and vitamins you are currently taking.
3. Disclose any recent illness, infection, surgery, or hospitalization, as these affect many laboratory values.
4. Disclose if you are pregnant or breastfeeding.
5. Arrive well-rested. Avoid overnight shifts, extremely early waking, or stressful events before collection where possible.
6. Drink adequate plain water during the fasting period to ensure good venous access and reduce the risk of hemolysis during blood draw.
7. Do not smoke for at least 30 minutes before blood collection.
8. Do not perform vigorous exercise on the day of blood collection unless the test is specifically a post-exercise assessment.
9. If you feel dizzy, lightheaded, or faint after blood collection, inform the laboratory staff immediately. Remain seated until you feel well enough to leave.
10. Results will be released according to the turnaround time of each test. MACE Diagnostic Center will notify you when your results are ready for pickup or release to your physician.

This guide is for informational purposes only and does not constitute medical advice. Clinical interpretation of all results must be performed by the attending physician. Reference ranges may vary depending on the analyzer, reagent system, and patient population, and are subject to change as clinical evidence evolves.

Hematology

Complete Blood Count (CBC)

Test Preparation Guide — for patients and healthcare providers

1. Overview

The Complete Blood Count is the most frequently ordered hematology test. It provides a comprehensive picture of the cellular elements of the blood, including counts and indices for red blood cells, white blood cells, and platelets. The CBC is used to screen for anemia, infection, clotting disorders, immune conditions, and hematologic malignancies.

2. Parameters Reported in a Standard CBC

Red Blood Cell Parameters

White Blood Cell Parameters

Platelet Parameters

3. Patient Preparation

Inform the Laboratory Of

• All current medications, especially anticoagulants (warfarin, heparin, aspirin, clopidogrel), immunosuppressants, chemotherapy agents, and corticosteroids — all of which significantly affect CBC parameters.
• Recent blood transfusions (within the past 4 months).
• Current illness, fever, or infection.
• Pregnancy or recent delivery.
• Any history of bone marrow disorders or hematologic conditions.

Specimen Handling Notes

• The blood sample must be gently mixed (inverted 8–10 times) immediately after collection to prevent clotting with the EDTA anticoagulant.
• Do NOT shake the tube vigorously — this causes platelet clumping and hemolysis, which will affect all CBC parameters.
• Process and run the specimen within 4 hours of collection for optimal accuracy; WBC differential and platelet morphology deteriorate with prolonged storage.
• Inform the laboratory if you are cold-agglutinin positive (certain autoimmune conditions), as cold temperatures cause RBC clumping and falsely lower the RBC count.

4. Reference Ranges (Adult)

Red Blood Cell Parameters

White Blood Cell Parameters

Platelet Parameters

Anemia Classification by CBC Indices

5. Factors Affecting Results

• Lipemia (high fat in blood after eating) can falsely elevate HGB
• Hemolysis falsely elevates MCHC and lowers platelet count
• Prolonged storage causes WBC and platelet deterioration
• EDTA-dependent pseudothrombocytopenia: platelet clumping in the EDTA tube causes a falsely low platelet count — a citrate tube may be used for confirmation if suspected
• Altitude — persons living at high altitude have physiologically higher RBC, HGB, and HCT values
• Pregnancy causes physiological dilutional anemia (lower HGB, HCT)

This guide is for informational purposes only and does not constitute medical advice. Clinical interpretation of all results must be performed by the attending physician. Reference ranges may vary depending on the analyzer, reagent system, and patient population.

Hematology

ABO Blood Typing

Test Preparation Guide — ABO Blood Group and Rh Typing

1. Overview

ABO Blood Typing determines a person’s blood group (A, B, AB, or O) and Rh factor (positive or negative) based on the antigens present on the surface of red blood cells and the antibodies present in the plasma. Blood typing is essential before blood transfusions, organ transplants, and in obstetric care to prevent hemolytic disease of the newborn (HDN).

2. Patient Preparation

Inform the Laboratory Of

• Recent blood transfusions (within the past 3 months) — transfused red cells from a donor may temporarily alter typing results, particularly in massive transfusion situations.
• Bone marrow or stem cell transplantation — may result in blood group conversion to donor type.
• Recent use of intravenous immunoglobulin (IVIG) or anti-D (Rh immunoglobulin / RhoGAM) — may affect antibody screen.
• Any known blood group discrepancies from previous typing.

• Two separate blood samples collected on different occasions may be required before blood transfusion as a safety protocol.
• For obstetric patients: Rh typing is performed to identify Rh-negative mothers who may require anti-D prophylaxis (RhoGAM) to prevent sensitization if carrying an Rh-positive fetus.

3. ABO Blood Group System

Rh Factor

4. Factors Affecting Results

• Recent transfusion with a different blood type (mixed cell population)
• Bone marrow transplant (chimerism)
• Certain diseases causing weakened antigen expression (leukemia, lymphoma, myelodysplastic syndrome)
• Rouleaux formation (multiple myeloma, high fibrinogen) causing false agglutination
• Cold agglutinins interfering with room-temperature testing

This guide is for informational purposes only and does not constitute medical advice. Clinical interpretation of all results must be performed by the attending physician. Reference ranges may vary depending on the analyzer, reagent system, and patient population.

Hematology

Clotting Time (CT) & Bleeding Time (BT)

Test Preparation Guide — for patients and healthcare providers

1. Overview

Clotting Time (CT) and Bleeding Time (BT) are bedside or near-patient tests that evaluate different phases of hemostasis (the process of stopping bleeding).

Bleeding Time (BT): Measures primary hemostasis — how quickly platelets form a plug at the site of a small wound. It reflects platelet function and the integrity of small blood vessels. Prolonged BT suggests platelet dysfunction or thrombocytopenia.

Clotting Time (CT): Measures the time for whole blood to clot in a glass tube (Lee-White method or capillary tube method). It reflects the intrinsic coagulation pathway (Factors VIII, IX, XI, XII). Prolonged CT suggests coagulation factor deficiency or anticoagulant effect.

2. Patient Preparation

For Bleeding Time (BT)

• No fasting is required.
• The test involves a small standardized skin puncture (usually on the forearm using a template device, or earlobe using a lancet). A small scar may be left at the test site; inform the laboratory if scarring is a concern.
• Roll up your sleeve and expose the forearm before the procedure.

For Clotting Time (CT)

• No fasting is required.
• Inform the laboratory of all anticoagulant medications:
  • Warfarin (Coumadin) — directly prolongs clotting time
  • Heparin (IV or subcutaneous) — directly prolongs CT
  • Direct oral anticoagulants (DOACs): rivaroxaban, apixaban, dabigatran — may affect CT
• Do NOT stop anticoagulants without physician guidance.
• Inform the laboratory of any known bleeding disorders (hemophilia A, hemophilia B, von Willebrand disease).

3. Reference Ranges & Interpretation

Note: Method-specific reference ranges apply. The laboratory will report which method was used alongside the result.

Interpretation

4. Factors Affecting Results

• Aspirin and NSAIDs (prolong BT)
• Anticoagulant medications (prolong CT)
• Thrombocytopenia — low platelet count (prolongs BT)
• Anemia — severe anemia can prolong BT
• Edematous or cold skin at the BT puncture site (slows platelet response)
• Improper pressure or wiping technique during BT
• Glass vs. silicone tube used for CT (glass activates clotting faster)

This guide is for informational purposes only and does not constitute medical advice. Clinical interpretation of all results must be performed by the attending physician. Reference ranges may vary depending on the analyzer, reagent system, and patient population.

Hematology

Erythrocyte Sedimentation Rate (ESR)

Test Preparation Guide — for patients and healthcare providers

1. Overview

The Erythrocyte Sedimentation Rate (ESR) measures how quickly red blood cells (erythrocytes) settle to the bottom of a vertical tube of anticoagulated blood over one hour. When inflammation, infection, or tissue injury is present, the liver produces more acute-phase proteins (especially fibrinogen), which coat red blood cells and cause them to clump (rouleaux) and settle faster — resulting in a higher ESR.

ESR is a nonspecific marker of inflammation and is used to:

• Screen for and monitor inflammatory and autoimmune conditions (rheumatoid arthritis, systemic lupus erythematosus, vasculitis)
• Monitor temporal arteritis and polymyalgia rheumatica (highly sensitive)
• Detect chronic infection (tuberculosis, osteomyelitis, endocarditis)
• Monitor response to treatment of inflammatory diseases

2. Patient Preparation

Inform the Laboratory Of

• Any current illness, fever, or known inflammatory condition, as these are the primary drivers of an elevated ESR.
• Pregnancy (physiologically elevates ESR throughout gestation).

3. Reference Ranges & Interpretation (Westergren Method)

Note: ESR increases physiologically with age. Some laboratories use the formula: Upper limit = Age (years) / 2 for males; (Age + 10) / 2 for females.

Interpretation

4. Factors Affecting Results

This guide is for informational purposes only and does not constitute medical advice. Clinical interpretation of all results must be performed by the attending physician. Reference ranges may vary depending on the analyzer, reagent system, and patient population.

Hematology

Hematocrit (HCT) & Hemoglobin (HGB)

Test Preparation Guide — for patients and healthcare providers

1. Overview

Hematocrit (HCT) and Hemoglobin (HGB) are the two primary indicators of anemia and polycythemia. While both are included in the CBC, they may be ordered as a standalone pair for rapid screening, monitoring of known anemia, or point-of-care assessment.

Hemoglobin (HGB): Measures the concentration of hemoglobin (the iron-containing, oxygen-carrying protein) in a given volume of blood. It directly reflects the oxygen-carrying capacity of the blood.

Hematocrit (HCT): Measures the percentage of total blood volume occupied by packed red blood cells after centrifugation. It is closely correlated to hemoglobin (HCT ≈ HGB × 3 as a rule of thumb).

2. Patient Preparation

Inform the Laboratory Of

• Pregnancy (physiological dilutional anemia)
• Current IV fluid therapy (hemodilution lowers both HGB and HCT)
• Recent blood transfusion
• Known anemia or polycythemia
• Altitude of residence (higher altitude = physiologically higher HGB and HCT)
• Smoking (chronic smokers have elevated HGB due to carboxyhemoglobin)

Specimen Notes

• For capillary HCT: warm the fingertip prior to puncture to improve blood flow. Avoid excessive squeezing (milking), as tissue fluid dilutes the sample and falsely lowers HCT.
• Fill the capillary tube completely; air bubbles affect centrifugation.

3. Reference Ranges

Anemia Grading by Hemoglobin (WHO)

4. Factors Affecting Results

• Lipemia falsely elevates HGB (turbidity in photometric measurement)
• High WBC count (> 30,000/µL) falsely elevates HGB
• Carboxyhemoglobin in smokers may falsely elevate HGB on some analyzers
• Overhydration or IV fluid infusion lowers both HGB and HCT
• Dehydration or prolonged tourniquet raises HCT (hemoconcentration)
• Delay in specimen processing may cause slight hemolysis

This guide is for informational purposes only and does not constitute medical advice. Clinical interpretation of all results must be performed by the attending physician. Reference ranges may vary depending on the analyzer, reagent system, and patient population.

Hematology

Peripheral Blood Smear (PBS)

Test Preparation Guide — for patients and healthcare providers

1. Overview

The Peripheral Blood Smear (PBS) is a microscopic examination of a thin film of blood spread on a glass slide, stained (typically with Wright-Giemsa stain), and examined under a microscope by a medical technologist or pathologist. It provides detailed morphological information about the size, shape, and appearance of red blood cells, white blood cells, and platelets that automated analyzers cannot fully capture.

PBS is ordered to:

• Confirm or characterize anemia identified by CBC
• Identify abnormal red cell morphology (sickle cells, target cells, schistocytes, acanthocytes, spherocytes)
• Evaluate white cell morphology (blasts, hypersegmented neutrophils, reactive lymphocytes, atypical cells)
• Identify platelet abnormalities (giant platelets, platelet clumps)
• Detect blood parasites (malaria, babesiosis, trypanosomiasis)
• Confirm an automated differential flagged by the analyzer

2. Patient Preparation

Inform the Laboratory Of

• All current medications, especially chemotherapy agents, hydroxyurea, methotrexate — these cause distinct morphological changes visible on smear (megaloblastic changes, hypersegmentation)
• Any known blood disorders, recent travel to malaria-endemic areas (critical for parasite detection), or exposure to toxins
• Recent blood transfusion (donor cells may obscure the patient’s own cell morphology)

3. What the Smear Reports

Red Cell Morphology

White Cell Morphology

4. Factors Affecting Results

• Delayed smear preparation (> 2 hours from EDTA collection) causes crenation, WBC nuclear changes, and platelet satellite artifact
• Refrigeration of EDTA blood prior to smearing
• Poor smear technique (too thick, too thin, uneven spread)
• Improper staining (overstained or understained slides)
• Lipemic or icteric blood may affect staining quality

This guide is for informational purposes only and does not constitute medical advice. Clinical interpretation of all results must be performed by the attending physician. Reference ranges may vary depending on the analyzer, reagent system, and patient population.

Hematology

Reticulocyte Count

Test Preparation Guide — for patients and healthcare providers

1. Overview

The Reticulocyte Count measures the percentage and absolute number of reticulocytes — immature red blood cells that have recently been released from the bone marrow into the bloodstream. Reticulocytes still contain remnant RNA (visible as a reticulum on supravital staining) and mature into fully functional RBCs within 1–2 days of entering circulation.

The reticulocyte count reflects the bone marrow’s red cell production activity and is used to:

• Determine whether the bone marrow is responding appropriately to anemia (high retic count = active production; low retic count = bone marrow failure or suppression)
• Classify anemia as hypoproliferative vs. hyperproliferative
• Monitor response to iron, B12, or folate replacement therapy (a rising reticulocyte count 5–10 days after starting therapy is the first sign of treatment response — called the “reticulocyte crisis” or reticulocyte response)
• Monitor bone marrow recovery after chemotherapy or bone marrow transplantation

2. Patient Preparation

Inform the Laboratory Of

• Recent initiation of iron supplementation, vitamin B12 injections, or folate therapy — expect a physiological rise in reticulocytes 5–10 days after starting treatment.
• Recent blood transfusion — donor reticulocytes will affect the count.
• Chemotherapy or immunosuppressive therapy — these suppress bone marrow and lower reticulocyte counts.
• Erythropoietin (EPO) therapy — significantly increases reticulocyte production.
• Known hemolytic anemia — the bone marrow compensates with markedly elevated reticulocyte counts.

Specimen Notes

• Process the specimen within 6 hours of collection for accurate counts.
• For manual reticulocyte count: the EDTA blood is mixed with supravital stain (new methylene blue) and a smear is prepared and examined under oil immersion.
• Refrigerate the sample at 4°C if processing is delayed beyond 6 hours; run within 24 hours.

3. Reference Ranges & Interpretation

Reticulocyte Production Index (RPI)

RPI corrects the reticulocyte % for the degree of anemia and for early release of reticulocytes from the marrow (shift cells). It provides a more accurate picture of effective erythropoiesis.

Formula: RPI = (Reticulocyte % × Patient HCT / Normal HCT) ÷ Maturation factor (1.0–2.5 depending on HCT level)

Interpretation

4. Factors Affecting Results

This guide is for informational purposes only and does not constitute medical advice. Clinical interpretation of all results must be performed by the attending physician. Reference ranges may vary depending on the analyzer, reagent system, and patient population.

Hematology

Quick Reference & Reminders

Hematology panel at a glance · general reminders for all hematology tests

1. Overview of Hematology Testing

Hematology tests examine the cellular components of blood — red blood cells, white blood cells, and platelets — as well as the blood’s clotting ability, sedimentation rate, and cell morphology. These tests are essential for the diagnosis and monitoring of anemia, infection, bleeding disorders, hematologic malignancies, and inflammatory conditions.

Tests Included

2. Hematology Panel at a Glance

3. General Reminders for Hematology Tests

1. None of the hematology tests listed require fasting. You may eat and drink normally before coming to the laboratory.
2. Always inform the laboratory of ALL medications, particularly anticoagulants, antiplatelet agents, corticosteroids, chemotherapy, and iron/vitamin supplements — these have direct and significant effects on hematology results.
3. Disclose any recent blood transfusion, surgery, or major illness, as these alter baseline hematology parameters for weeks to months.
4. Disclose any recent travel to malaria-endemic areas if a blood smear is being requested, so that specific malaria smear protocols are used.
5. Gently mix the EDTA tube immediately after collection. Do NOT shake vigorously. Vigorous shaking causes platelet clumping and hemolysis.
6. For ESR: the citrate tube must be filled exactly to the marked line. Inform collection staff if you have small or difficult veins so an appropriate needle size can be selected.
7. For Bleeding Time: do NOT apply lotion, cream, or topical products to the forearm on the day of the test, as these affect the skin’s response to the puncture.
8. Results will be available within the turnaround time listed for each test. MACE Diagnostic Center will notify you when results are ready for pickup or release to your physician.

This guide is for informational purposes only and does not constitute medical advice. Clinical interpretation of all results must be performed by the attending physician. Reference ranges may vary depending on the analyzer, reagent system, and patient population.

Clinical Microscopy

Urinalysis

Test Preparation Guide — Routine Urinalysis with Microscopy

1. Overview

Routine Urinalysis (UA) is a group of physical, chemical, and microscopic tests performed on a urine sample. It is one of the most widely ordered screening tests in clinical practice and is used to evaluate kidney function, detect urinary tract infections, screen for diabetes and liver disease, and monitor a wide range of systemic conditions.

2. Components of a Routine Urinalysis

Physical Examination

Chemical Examination (Dipstick)

Microscopic Examination

3. Specimen Collection — Midstream Clean-Catch

1. Obtain a clean, sterile urine cup from the laboratory reception. Do NOT use any container from home unless specifically approved.
2. Wash your hands thoroughly with soap and water.
3. Females — Spread the labia with one hand. Using the antiseptic wipe provided, clean from front to back (one wipe per stroke — do NOT wipe back to front). Use at least 2 wipes. Males — Retract the foreskin (if uncircumcised). Clean the tip of the penis with the antiseptic wipe using a circular motion.
4. Begin urinating into the toilet bowl. After 1–2 seconds, WITHOUT stopping the urine flow, move the cup into the stream and collect the MIDSTREAM portion (approximately 30–50 mL). Finish urinating into the toilet.
5. Cap the container immediately. Avoid touching the inside of the cup or lid. Label the container with your full name and date.
6. Submit the specimen to the laboratory immediately. Urine should be processed within 1–2 hours of collection. If delayed, refrigerate at 4°C for no more than 4 hours. Do NOT leave urine at room temperature for more than 2 hours, as cells and casts degrade rapidly, bacteria multiply, and pH shifts — all of which will affect results.

Special Considerations

Menstruating Females

• If possible, avoid collecting a urine specimen during menstruation. Menstrual blood will contaminate the specimen and produce a false-positive result for blood and red blood cells.
• If the test is urgent and cannot be postponed, insert a clean tampon before collection and use the clean-catch midstream technique. Note on the request form that the patient is menstruating.

Protein (Orthostatic / Postural Proteinuria)

• If the physician is evaluating for orthostatic proteinuria, a first morning void (collected before rising and activity) is essential, as protein may be elevated in urine collected after standing or physical activity in some individuals — a benign condition.

Pediatric Patients

• For infants and non-ambulatory children, a sterile adhesive pediatric urine collection bag is available at the laboratory.
• For older children, assist with the clean-catch midstream technique.

Foley Catheter Patients

• Do NOT collect urine from the drainage bag (stagnant, not representative of current urine). Collect from the catheter sampling port using a sterile syringe after clamping the tubing for 15–30 minutes. Inform the laboratory.

4. Reference Ranges

HPF = High-Power Field (400× magnification)

5. Factors Affecting Results

• Contamination with vaginal discharge, menstrual blood, or skin bacteria (most common pre-analytical error)
• Prolonged time between collection and processing (degrades cells, casts; pH shifts; bacteria multiply)
• Highly dilute urine (overhydration) lowers specific gravity and may dilute cells and protein below detectable levels
• Concentrated urine (dehydration) may cause false-positive protein and elevated SG
• Vitamin C (ascorbic acid) in high doses falsely suppresses the dipstick reaction for glucose, blood, nitrite, and bilirubin
• Strenuous exercise before collection (jogging to the lab) can cause transient hematuria and proteinuria

Foods and Medications That Alter Urine Color

This guide is for informational purposes only and does not constitute medical advice. All results must be interpreted by the attending physician in the context of the patient’s clinical history, symptoms, and other diagnostic findings.

Clinical Microscopy

Fecalysis

Test Preparation Guide — Routine Fecal Examination

1. Overview

Fecalysis (also called a Stool Examination or Routine Fecal Analysis) is a macroscopic, chemical, and microscopic examination of a stool specimen. It is used to detect intestinal parasites (ova, cysts, larvae, adult worms), bacterial pathogens, blood, mucus, and abnormal cells in the gastrointestinal tract. It is commonly requested for gastrointestinal complaints, pre-employment screening, and pediatric health evaluations.

2. Components of Fecalysis

Macroscopic Examination

Microscopic Examination

3. Specimen Collection

1. Obtain a clean stool container from the laboratory reception. Do NOT use a container from home unless specifically provided and approved by the laboratory.
2. Defecate into a clean, dry bedpan or potty. Do NOT defecate directly into the toilet, as the specimen must not be contaminated with toilet water, urine, or cleaning agents. If at home, line the toilet seat with clean newspaper or plastic wrap to catch the stool, then transfer a portion.
3. Using the spoon attached to the lid of the container, collect samples from DIFFERENT AREAS of the stool: the outer surface, the center (core), and any area that appears abnormal (mucus, blood, unusual color or consistency). Collect approximately the amount of a large walnut.
4. Do NOT fill the container to the top — fill only one-third to half. Overfilling can contaminate the lid and make the container difficult to close securely.
5. Seal the container tightly. Label it with your full name and date and time of collection.
6. Submit to the laboratory IMMEDIATELY or within 30–60 minutes of collection. The specimen must be FRESH: trophozoites of Entamoeba histolytica survive only 30–60 minutes after defecation at room temperature and will NOT be detectable in a stale specimen. Giardia cysts are more stable but still best examined fresh. For best results: collect early in the morning and bring directly to the laboratory upon opening.

4. Reference Ranges

5. Factors Affecting Results

• Delay in submission (trophozoite death — false negative for ameba)
• Urine contamination (destroys trophozoites)
• Recent antibiotics (suppress parasite load)
• Recent barium, mineral oil, or bismuth preparations
• Single specimen only (reduces sensitivity for parasites)
• Menstrual contamination (false positive for blood)
• Prolonged constipation (stool stasis alters morphology of parasites)

This guide is for informational purposes only and does not constitute medical advice. All results must be interpreted by the attending physician in the context of the patient’s clinical history, symptoms, and other diagnostic findings.

Clinical Microscopy

Fecal Occult Blood Test (FOBT)

Test Preparation Guide — for patients and healthcare providers

1. Overview

The Fecal Occult Blood Test (FOBT) detects microscopic (hidden, invisible to the naked eye) blood in the stool. It is used primarily to screen for colorectal cancer and polyps, and to investigate gastrointestinal bleeding from ulcers, gastritis, or inflammatory bowel disease.

“Occult” means hidden — the test detects blood that produces no visible discoloration of the stool.

2. Dietary Restrictions — 3 Days Before and During Collection

Note: The immunochemical FOBT (iFOBT/FIT) is specific to HUMAN hemoglobin and does NOT require the above dietary restrictions. Confirm with the laboratory which method is being used.

3. Medication Restrictions — 7 Days Before and During Collection

Medications to Avoid (cause false-positive results or GI bleeding)

• Aspirin (including low-dose 80 mg) — causes gastric irritation and microbleeding even at low doses
• NSAIDs (ibuprofen, naproxen, mefenamic acid, diclofenac)
• Anticoagulants (warfarin, heparin) — increase likelihood of GI microbleeding
• Iron supplements — cause false-positive reactions with the guaiac method
• Corticosteroids (long-term use may cause GI bleeding)

Medications Permitted — unless otherwise instructed by physician

• Antacids (calcium carbonate, aluminum hydroxide)
• Acetaminophen / Paracetamol (safe alternative to aspirin/NSAIDs)
• Proton pump inhibitors (omeprazole, pantoprazole)
• Antihypertensives, diabetes medications, thyroid medications

Do NOT stop any prescribed medication without explicit physician guidance. If aspirin or anticoagulants cannot be safely stopped, inform the physician before proceeding — the test may need to be rescheduled or the results interpreted with caution.

4. Specimen Collection (Guaiac Card Method)

The laboratory will provide you with a test card kit containing three FOBT cards (labeled Day 1, Day 2, Day 3), a wooden applicator stick (or brush) for each card, and instructions specific to the brand of card used.

1. On each of three separate days (not necessarily consecutive; every other day is acceptable), collect a small stool sample.
2. Using the wooden applicator stick, apply a THIN SMEAR of stool from one area of the sample onto the first box (labeled A) of the card. Then take a smear from a DIFFERENT AREA of the same stool and apply to the second box (labeled B) of the same card. Sampling two different areas of the same stool increases detection sensitivity.
3. Close the card flap and store in a cool, dry place away from direct sunlight, heat, or moisture (do NOT refrigerate the guaiac card — moisture affects the guaiac paper). Complete the remaining two cards on subsequent days.
4. After all three cards are completed, submit ALL three cards to the laboratory as soon as possible and no later than 6 days after the first collection. Cards must NOT be mailed unless using a specific postal FOBT kit approved for this purpose.
5. The laboratory will apply developer solution to the back of each card and read the result within 60 seconds: any blue color = POSITIVE (blood detected); no blue color = NEGATIVE.

5. Results & Interpretation

A positive FOBT does NOT automatically mean colorectal cancer. Many conditions cause a positive result, including:

• Hemorrhoids (most common cause of false-positive)
• Peptic ulcer or gastric erosion
• Inflammatory bowel disease (Crohn’s disease, ulcerative colitis)
• Esophagitis or esophageal varices
• Polyps (which can be pre-cancerous)
• Colorectal cancer (the condition FOBT is designed to screen for)
• Dietary sources (if restrictions were not followed)

6. Factors Affecting Results

This guide is for informational purposes only and does not constitute medical advice. All results must be interpreted by the attending physician in the context of the patient’s clinical history, symptoms, and other diagnostic findings.

Clinical Microscopy

Urine Pregnancy Test (hCG)

Test Preparation Guide — Urine Human Chorionic Gonadotropin (hCG)

1. Overview

The Urine Pregnancy Test detects Human Chorionic Gonadotropin (hCG) in the urine. hCG is a hormone produced by the trophoblast cells of the developing placenta shortly after the fertilized egg implants in the uterine wall, typically 6–12 days after fertilization. hCG levels double approximately every 48–72 hours in the first trimester of a normal pregnancy and are detectable in urine within 12–15 days after conception.

The test is a rapid qualitative immunoassay (lateral flow or ELISA) that detects hCG above a threshold concentration (typically 20–25 mIU/mL).

2. Patient Preparation

Timing

• The test can be performed as early as the FIRST DAY OF A MISSED PERIOD (approximately 14 days after conception) for reliable results.
• Testing too early (before implantation is complete) may yield a false-negative result because hCG levels may not yet be above the detection threshold.
• If the test is negative but pregnancy is still suspected, repeat the test 3–7 days later (hCG levels will have doubled if pregnant) or request a quantitative serum beta-hCG from your physician.

First Morning Void

• The first morning urine is the most concentrated of the day and contains the highest hCG levels, making it the ideal specimen, especially in the very early stages of pregnancy (1–2 weeks after a missed period).
• A random urine sample is acceptable but may give a weaker result if hCG levels are still low.

Hydration

• Avoid drinking excessive amounts of water or fluids immediately before the test. Overhydration dilutes the urine and reduces hCG concentration, potentially causing a false-negative result.

Medications

• Most over-the-counter and prescription medications do NOT affect the urine hCG test. The following are exceptions:
  • hCG injections (Pregnyl, Novarel, Ovidrel) used for fertility treatment will cause a TRUE POSITIVE result for several days to weeks after injection, even if pregnancy has not occurred. Inform the laboratory if you have received hCG injections.
  • Methotrexate (used to treat ectopic pregnancy) — may cause persistently elevated hCG during treatment.
  • No other common medications (antibiotics, birth control pills, NSAIDs, antihypertensives) affect urine hCG results.

Specimen Collection

• Collect urine using the midstream clean-catch technique (same as described in the Urinalysis guide).
• Alternatively, if using a point-of-care strip at the laboratory, the first few seconds of urine may be used — follow laboratory staff instructions.

3. Result Interpretation

4. Factors Affecting Results

This guide is for informational purposes only and does not constitute medical advice. All results must be interpreted by the attending physician in the context of the patient’s clinical history, symptoms, and other diagnostic findings.

Clinical Microscopy

Quick Reference & Reminders

Clinical microscopy at a glance · general reminders for all tests

1. Overview of Clinical Microscopy

Clinical Microscopy involves the macroscopic, chemical, and microscopic examination of body fluids — primarily urine and feces — to detect and monitor diseases of the urinary tract, gastrointestinal system, kidneys, and other organ systems. These tests are among the most frequently requested in a diagnostic laboratory and are essential components of routine health screening and pre-employment examinations.

Tests Included

2. Clinical Microscopy at a Glance

3. General Reminders for Clinical Microscopy

1. Obtain ALL specimen containers from MACE Diagnostic Center. Do NOT use containers from home (food jars, water bottles, plastic bags). Laboratory-grade containers are sterile, properly labeled, and compatible with our processing equipment.
2. Label all specimens with your FULL NAME and DATE AND TIME OF COLLECTION before submitting to the laboratory.
3. Handle all specimen containers with care. Leaking, broken, or grossly contaminated containers will be rejected and a new specimen must be collected.
4. Submit all urine and stool specimens to the laboratory AS SOON AS POSSIBLE after collection. Time from collection to processing is critical for accurate results, especially for fecalysis.
5. Inform the laboratory of all current medications, supplements, and any recent procedures that may affect results.
6. Inform the laboratory if you are menstruating, as this can affect urinalysis, fecalysis, FOBT, and urine pregnancy test results.
7. For FOBT: keep the completed test cards in a cool, dry location away from direct sunlight. Do NOT refrigerate the guaiac cards.
8. For the Pregnancy Test: a positive result requires follow-up with a physician for clinical confirmation, gestational age estimation, and prenatal care planning.
9. Results will be available within the turnaround time stated for each test. MACE Diagnostic Center will notify you when results are ready for pickup or release to your physician.

This guide is for informational purposes only and does not constitute medical advice. All results must be interpreted by the attending physician in the context of the patient’s clinical history, symptoms, and other diagnostic findings. Reference ranges and diagnostic criteria are based on current international laboratory guidelines and are subject to change. Results should be correlated with clinical findings before any medical decision is made.

Immunoserology

Cardiac Panel

Test Preparation Guide — Troponin-I, Troponin-T, NT-proBNP, D-Dimer, CK-MB, Myoglobin

1. Overview

The Cardiac Panel is a group of biomarkers used in the rapid evaluation of suspected acute myocardial infarction (heart attack), heart failure, pulmonary embolism, and other cardiovascular emergencies. These markers are released into the bloodstream when cardiac or vascular tissue is damaged, and each has a distinct rise-and-fall kinetic profile that helps determine the timing and extent of injury.

2. Tests & Temporal Profile

Biomarker Temporal Profile (hours after onset of chest pain)

3. Patient Preparation

Serial testing is standard: troponin is typically measured at presentation, then at 3 hours, and again at 6 hours to detect the characteristic rise-and-fall pattern of AMI.

Inform the Laboratory Of

• Time of chest pain onset (critical for result interpretation)
• Recent strenuous physical exercise (elevates myoglobin and CK-MB from skeletal muscle; may slightly elevate troponin)
• Recent intramuscular injections (elevate CK-MB, myoglobin)
• Recent surgery, cardioversion, or cardiac catheterization (can cause troponin elevation from procedural myocardial injury)
• Chronic kidney disease (CKD) — significantly elevates NT-proBNP and can mildly elevate troponin due to reduced clearance
• Pulmonary embolism, sepsis, myocarditis, or heart failure — all elevate troponin without coronary artery occlusion

4. Reference Ranges

Note: All decision values are method- and analyzer-dependent. The laboratory’s instrument-specific 99th percentile reference limit applies.

5. Factors Affecting Results

• Hemolysis — falsely elevates troponin on some immunoassay platforms
• Skeletal muscle injury, rhabdomyolysis — elevates CK-MB and myoglobin
• CKD — elevates NT-proBNP and TnT (reduced renal clearance)
• Obesity — lower NT-proBNP (adipocyte clearance of BNP)
• D-Dimer: elevated in pregnancy, postoperative state, infection, malignancy, age > 50 — NOT specific for DVT/PE alone
• Heterophile antibodies — can cause falsely elevated troponin in some immunoassay formats (human anti-mouse antibody / HAMA interference)

This guide is for informational purposes only and does not constitute medical advice. All results must be interpreted by the attending physician in the context of the patient’s clinical history, symptoms, and other diagnostic findings.

Immunoserology

Dengue Panel

Test Preparation Guide — NS1 Antigen, Dengue IgG, Dengue IgM

1. Overview

The Dengue Panel detects dengue virus infection through two mechanisms: direct antigen detection (NS1) and antibody detection (IgG and IgM). Dengue fever is caused by the dengue virus (DENV serotypes 1–4) and is transmitted by the Aedes aegypti mosquito. It is endemic in the Philippines and is a leading cause of febrile illness requiring laboratory confirmation.

2. Tests & Diagnosis by Day of Illness

Dengue Diagnosis by Day of Illness

3. Patient Preparation

Inform the Laboratory Of

• Exact day of illness / date and time of fever onset (critical for interpreting which test is expected to be positive)
• Maximum body temperature recorded
• Any antipyretic or antibiotic medications taken
• Travel history and location of possible exposure
• Prior dengue infection or dengue vaccination history (affects IgG interpretation — prior vaccination or infection causes baseline IgG elevation)
• A Complete Blood Count should be requested alongside the Dengue Panel; thrombocytopenia (low platelet count) and hemoconcentration are hallmarks of dengue disease progression

4. Reference Ranges

5. Factors Affecting Results

• Testing too early: NS1 negative before Day 1 (no viremia yet)
• Testing too late: NS1 negative after Day 9 (viremia cleared)
• False-positive NS1: seen with other flavivirus infections (Zika, chikungunya, Japanese encephalitis) and rheumatoid factor
• False-positive IgM/IgG: cross-reactivity with other flaviviruses; recent dengue vaccination
• False-negative IgM in secondary dengue (IgG dominates the response)
• Severe dengue (DHF/DSS): may have NS1 clearance earlier due to immune complex formation

This guide is for informational purposes only and does not constitute medical advice. All results must be interpreted by the attending physician in the context of the patient’s clinical history, symptoms, and other diagnostic findings.

Immunoserology

Infectious Panel — Hepatitis Markers

Test Preparation Guide — HBsAg, Anti-HBs, HBc IgM, HAV IgM, Anti-HAV Total, Anti-HCV

1. Overview

The Infectious Panel for hepatitis evaluates exposure to and infection with Hepatitis A (HAV), Hepatitis B (HBV), and Hepatitis C (HCV) viruses. These tests detect viral antigens and host-generated antibodies to determine current infection, past exposure, immunity, or carrier state. Hepatitis testing is essential for diagnosis, screening of high-risk groups, blood donor screening, and occupational health evaluation.

2. Tests & Interpretation

Hepatitis B

Hepatitis A

Hepatitis C

Hepatitis B Serology Interpretation Guide

HAV Interpretation

3. Patient Preparation

Inform the Laboratory Of

• Prior hepatitis vaccination (Hepatitis A and B vaccines) — this will cause positive Anti-HBs and Anti-HAV Total.
• Known liver disease, jaundice, or previous hepatitis diagnosis.
• Recent blood transfusion or organ transplantation.
• Immunosuppressive therapy — may blunt antibody responses.
• Immunoglobulin administration (IVIG) — may cause transient false-positive IgM results.
• Intravenous drug use, sexual history, or occupational exposure (relevant for risk stratification and result interpretation).

4. Reference Ranges

5. Factors Affecting Results

• Hemolysis and lipemia can interfere with immunoassay detection
• IVIG or blood transfusion — passive antibody transfer causing transient false-positive IgM
• Autoimmune conditions (SLE, rheumatoid factor) — can cause nonspecific antibody reactivity (false positives)
• Window period in HBV — all markers may be negative during this phase
• Immunosuppressed patients — may fail to mount detectable antibody responses (false negatives)
• Occult HBV — HBsAg negative but HBV DNA detectable by PCR

This guide is for informational purposes only and does not constitute medical advice. All results must be interpreted by the attending physician in the context of the patient’s clinical history, symptoms, and other diagnostic findings.

Immunoserology

Inflammation Panel

Test Preparation Guide — C-Reactive Protein (CRP), Procalcitonin, ASO Titer

1. Overview

The Inflammation Panel measures markers of systemic inflammation and infection. These tests help distinguish bacterial from viral infections, detect and monitor inflammatory conditions, and assess the risk of complications in acutely ill patients.

2. Tests & Clinical Role

3. Patient Preparation

Inform the Laboratory Of

• All current medications — corticosteroids and NSAIDs suppress CRP and may lower it even in active infection.
• Recent viral or bacterial illness, surgery, or trauma.
• Autoimmune conditions — CRP may be chronically elevated.
• For ASO Titer: recent sore throat, fever, or skin infection (impetigo); date of symptom onset (critical for interpreting titer level); whether penicillin or amoxicillin was already started (antibiotics suppress ASO rise).

4. Reference Ranges

5. Factors Affecting Results

• Corticosteroids and NSAIDs suppress CRP and PCT
• Early antibiotic use may blunt ASO titer rise
• Liver disease: CRP may be falsely low (impaired synthesis)
• CKD and dialysis patients: PCT may be mildly elevated at baseline
• Vigorous exercise: transient CRP elevation up to 24 hours after
• Lipemia and hemolysis: interfere with the turbidimetric CRP assay

This guide is for informational purposes only and does not constitute medical advice. All results must be interpreted by the attending physician in the context of the patient’s clinical history, symptoms, and other diagnostic findings.

Immunoserology

Thyroid Panel

Test Preparation Guide — T3, T4, Free T3 (FT3), Free T4 (FT4), TSH

1. Overview

The Thyroid Panel evaluates the function of the thyroid gland, which produces hormones that regulate metabolism, growth, body temperature, heart rate, and energy production. These tests are used to diagnose hypothyroidism and hyperthyroidism, monitor thyroid replacement therapy and antithyroid treatment, and screen neonates for congenital hypothyroidism.

2. Tests & Testing Sequence

Recommended Testing Sequence

1. Start with TSH alone for initial thyroid screening.
2. If TSH is abnormal: for elevated TSH, add FT4 to confirm and grade hypothyroidism; for suppressed TSH, add FT4 and FT3 to confirm and classify hyperthyroidism.
3. The full panel (T3, T4, FT3, FT4, TSH) may be ordered upfront for comprehensive evaluation or monitoring of known thyroid disease.

3. Patient Preparation

Thyroid Medications — Timing

• Levothyroxine (T4 replacement): draw blood BEFORE taking the morning dose (pre-dose sample). Taking the pill 4–6 hours before collection will cause a transient spike in FT4 that overestimates the steady-state level.
• Methimazole, propylthiouracil (PTU), carbimazole: inform the laboratory of dose and timing.

Medications Affecting Thyroid Test Results

Also Inform the Laboratory Of

• Pregnancy: physiologic changes during pregnancy alter all thyroid parameters significantly; trimester-specific reference ranges apply.
• Recent iodine exposure: iodinated contrast for CT scans or radioiodine therapy affects thyroid function.
• Acute non-thyroidal illness (euthyroid sick syndrome) — severe systemic illness causes marked suppression of T3 and T4 with variable TSH, mimicking thyroid disease.

4. Reference Ranges

Thyroid Dysfunction Pattern

5. Factors Affecting Results

• Biotin supplements > 5 mg/day (critical interference — see above)
• Levothyroxine taken within 4–6 hours of collection (elevates FT4)
• Amiodarone: blocks T4→T3 conversion; independently affects thyroid
• Pregnancy: trimester-specific ranges apply (TSH lower in first trimester)
• Severe illness (euthyroid sick syndrome) mimics hypothyroidism
• Heterophile antibodies: can cause spuriously elevated TSH
• Estrogen/OCP: elevates total T4/T3 (not FT4/FT3)

This guide is for informational purposes only and does not constitute medical advice. All results must be interpreted by the attending physician in the context of the patient’s clinical history, symptoms, and other diagnostic findings.

Immunoserology

Tumor Markers

Test Preparation Guide — TPSA, CA-125, CA 15-3, CA 19-9

1. Overview

Tumor markers are substances (proteins, antigens, or hormones) produced by cancer cells or by normal cells in response to cancer, which can be detected and measured in the blood. They are used primarily for monitoring known malignancy, assessing treatment response, and detecting recurrence. They are NOT reliable as standalone screening tests in asymptomatic individuals due to low specificity — many benign conditions elevate tumor markers.

2. Tests & Clinical Role

3. Patient Preparation

TPSA (Total PSA)

• Avoid ejaculation for at least 48 hours before blood collection (transiently elevates PSA for 24–48 hours).
• Avoid vigorous physical activity, cycling, and horseback riding for at least 48 hours before testing — perineal pressure elevates PSA.
• Avoid digital rectal examination (DRE) for at least 48 hours before blood draw. DRE causes mechanical PSA release.
• Avoid prostate massage for at least 1 week before collection.
• Avoid cystoscopy, urethral catheterization, or prostate biopsy for at least 6 weeks before collection — these cause major PSA elevation.
• Do NOT collect blood for PSA during active prostatitis or urinary tract infection — both significantly elevate PSA. Treat the infection first, then repeat PSA testing after 6–8 weeks.
• 5-alpha-reductase inhibitors (finasteride / Propecia / Proscar; dutasteride / Avodart) reduce PSA by approximately 50% after 6 months of use. Inform the physician — the measured PSA value must be DOUBLED to approximate the true PSA when on these drugs.

CA-125 (for female patients)

• Menstruation elevates CA-125 due to normal shedding of endometrial cells. Avoid testing during menstruation if the result is for baseline monitoring (may yield falsely elevated CA-125 up to 2–3 times the upper limit of normal).
• First trimester of pregnancy: CA-125 is physiologically elevated. Inform the laboratory if pregnant.
• Endometriosis and pelvic inflammatory disease chronically elevate CA-125 — inform the physician of these conditions.

CA 15-3

• No specific pre-collection restrictions.
• Inform of current breast cancer treatment (chemotherapy, hormone therapy, radiation) — a rising CA 15-3 during treatment suggests disease progression; a falling value indicates response.

CA 19-9

• No specific pre-collection restrictions.
• Inform of any pancreatitis, cholestasis, or biliary obstruction, as these benign conditions significantly elevate CA 19-9.
• If the patient is Lewis antigen-negative (known from prior testing), CA 19-9 will always be undetectable regardless of disease status.

4. Reference Ranges

5. Factors Affecting Results

• Hemolysis and lipemia interfere with immunoassay-based tumor markers
• PSA: ejaculation, DRE, prostatitis, catheterization, finasteride
• CA-125: menstruation, pregnancy, endometriosis, liver disease, PID
• CA 15-3: liver disease, lung disease, benign breast disease
• CA 19-9: pancreatitis, cholestasis, Lewis antigen-negative status
• All tumor markers: heterophile antibodies and HAMA can cause spuriously elevated values in some immunoassay platforms

This guide is for informational purposes only and does not constitute medical advice. All results must be interpreted by the attending physician in the context of the patient’s clinical history, symptoms, and other diagnostic findings.

Immunoserology

HIV Screening

Test Preparation Guide — 4th-generation combined HIV Ag/Ab immunoassay

1. Overview

HIV Screening detects antibodies and/or antigens related to Human Immunodeficiency Virus (HIV), the virus that causes Acquired Immunodeficiency Syndrome (AIDS). Modern HIV screening tests are 4th-generation combined antigen/antibody (Ag/Ab) immunoassays that detect both HIV-1/HIV-2 antibodies AND the p24 antigen simultaneously, allowing earlier detection than antibody-only tests.

A reactive (positive) screening test MUST be confirmed by a more specific confirmatory test (HIV antibody differentiation assay or HIV RNA PCR) before a diagnosis of HIV is made or communicated.

2. Legal & Consent Requirements (RA 11166)

• Informed consent MUST be obtained from the patient before HIV testing. MACE Diagnostic Center will provide a consent form. You must sign the consent form before your blood is collected for HIV testing.
• Testing is CONFIDENTIAL. Results will be released ONLY to the patient or a designated authorized representative. Results will NOT be released to employers, insurance companies, family members, or other third parties without the patient’s explicit written consent.
• Pre-test and post-test counseling are available and may be offered by the laboratory or referring physician.
• HIV testing is VOLUNTARY. No person may be compelled to undergo HIV testing without their free, prior, and informed consent, except as provided by law (e.g., blood banking).

3. Patient Preparation & Window Period

Inform the Laboratory Of

• Recent exposure history (date of most recent potential exposure) — this is critical for interpreting a negative result.
• Prior HIV testing and results.
• Current antiretroviral therapy (ART) — patients on PrEP (pre-exposure prophylaxis) or treatment may have test results that require special interpretation.
• Autoimmune conditions or recent immunoglobulin (IVIG) therapy — may cause transient false-positive screening results.

4. Result Interpretation

Confirmatory Testing Algorithm (DOH Philippines)

1. Reactive 4th-gen screening test at MACE Diagnostic Center.
2. Repeat with a different screening assay (2nd test).
3. If both reactive, refer to a DOH-designated Confirmatory Laboratory (Social Hygiene Clinic / STI/AIDS Cooperative Central Laboratory / SACCL) for HIV Western Blot or HIV antibody differentiation assay.
4. HIV RNA PCR (viral load) as needed for indeterminate results.

5. Factors Affecting Results

MACE Diagnostic Center follows DOH and RA 11166 protocols for all HIV-reactive preliminary results, including immediate referral for confirmatory testing, counseling, and linkage to care.

This guide is for informational purposes only and does not constitute medical advice. All results must be interpreted by the attending physician in the context of the patient’s clinical history, symptoms, and other diagnostic findings.

Microbiology

Gram Stain

Test Preparation Guide — for patients and healthcare providers

1. Overview

The Gram Stain is a rapid, differential staining technique used to classify bacteria into two major groups based on the composition of their cell walls: Gram-positive (retaining crystal violet dye — appear PURPLE) and Gram-negative (losing crystal violet after decolorization, then retaining safranin counterstain — appear PINK/RED). The result also characterizes the morphology (shape) and arrangement of the organisms seen, providing critical information to guide empiric antibiotic therapy within hours — long before culture results are available.

The Gram Stain is one of the fastest and most cost-effective microbiological tests available. It is performed on a wide variety of specimens depending on the site of infection.

Specimen Types Accepted

2. What the Gram Stain Reports

3. Specimen Collection by Type

Sputum (for lower respiratory infection)

• Collect in the EARLY MORNING before eating, drinking, or brushing teeth. Morning sputum has the highest bacterial concentration.
• Rinse the mouth with plain water only (do NOT use mouthwash or toothpaste) to reduce oral flora contamination.
• Take a deep breath and cough forcefully from deep in the chest — expectorating from the LUNGS, not the throat or nasopharynx.
• Collect into a sterile, wide-mouth sputum container. A minimum of 1–3 mL of LOWER RESPIRATORY material is required.
• Saliva alone is NOT acceptable. If you cannot produce sputum, inform the laboratory — hypertonic saline nebulization (induced sputum) may be arranged with a physician’s order.
• Submit to the laboratory within 2 hours. If delayed, refrigerate at 4°C and submit within 24 hours.

Wound Swab / Pus

• Clean the wound surface of superficial debris with sterile saline before swabbing — do NOT apply antiseptic to the wound surface before collection as this kills surface bacteria.
• Swab the deepest accessible part of the wound or aspirate pus from the center of the abscess using a sterile syringe.
• Place the swab in transport medium immediately and seal.
• Do NOT allow the swab to dry out — submit within 2 hours.

Urethral Swab (males — for gonorrhea)

• Do NOT urinate for at least 1 hour before collection.
• A thin urogenital swab is inserted 2–3 cm into the urethra, rotated gently, and held for 5 seconds before withdrawing.
• A Gram stain showing intracellular gram-negative diplococci is strongly presumptive for Neisseria gonorrhoeae.

Vaginal / Cervical Swab

• Avoid douching, vaginal creams, or sexual intercourse for at least 24 hours before collection.
• Collected by the physician or trained nurse using a speculum.
• For bacterial vaginosis: the Gram stain (Nugent scoring) of a vaginal smear is the gold standard for diagnosis.

Ear and Eye Swabs

• Submit immediately in transport medium.
• Do NOT apply antibiotic drops to the ear or eye before collection.

4. Reference Ranges

The Gram stain is a PRESUMPTIVE test. Culture and sensitivity testing (C&S) is required for definitive identification and antibiotic susceptibility.

5. Factors Affecting Results

• Antibiotic therapy prior to collection — significantly reduces or eliminates organisms from the specimen (false negative)
• Specimen contamination with skin or oral flora (sputum, wound swabs)
• Dry swab or delayed transport without transport medium — organisms die
• Over-decolorization — Gram-positive organisms appear Gram-negative
• Under-decolorization — Gram-negative organisms appear Gram-positive
• Poor smear technique (too thick, uneven) — obscures morphology
• Certain organisms (Mycobacteria, Legionella, Chlamydia) do NOT stain well with standard Gram stain; specific stains are required

This guide is for informational purposes only and does not constitute medical advice. All results must be interpreted by the attending physician in the context of the patient’s clinical history, symptoms, and other diagnostic findings.

Microbiology

KOH (Potassium Hydroxide) Preparation

Test Preparation Guide — fungal wet mount for skin, nail, hair, and mucosal specimens

1. Overview

The KOH Preparation (Potassium Hydroxide Wet Mount) is a rapid microscopic technique used to detect fungal elements (hyphae, pseudohyphae, spores, and yeast cells) in clinical specimens. KOH dissolves the keratin in skin, hair, and nail material — as well as cellular debris in other specimens — while leaving fungal cell walls intact, making fungal structures clearly visible under the microscope.

It is the primary rapid test for diagnosing superficial and cutaneous fungal infections (dermatophytoses), as well as mucocutaneous candidiasis and tinea versicolor.

Specimen Types Accepted

2. Specimen Collection by Type

Skin Scrapings (tinea corporis, pedis, cruris)

• Do NOT apply antifungal creams, powders, or topical treatments to the affected skin for at least 72 hours (3 days) before collection.
• Avoid bathing or washing the area immediately before collection.
• Scrape material from the ACTIVE BORDER / EDGE of the lesion (the advancing scaly margin), NOT the center. The center of a ringworm lesion is often healing and contains the fewest organisms.
• Use a blunt scalpel, the edge of a glass slide, or a clean curette. Scrape firmly but gently to collect scales without drawing blood.
• Collect onto clean black paper or directly into a labeled sterile container. Collect a generous amount of scales — inadequate material is a major cause of false-negative KOH.

Nail Clippings and Subungual Scrapings (onychomycosis)

• Do NOT use antifungal nail lacquers or oral antifungal therapy for at least 2–4 weeks before collection (oral antifungals terbinafine, itraconazole persist in nails for weeks to months).
• Clip and collect the DISTAL portion of the abnormal nail plate (the most crumbly, discolored, and thickened section).
• Also scrape the SUBUNGUAL DEBRIS from under the free edge of the nail — this debris contains the highest concentration of hyphae and is the most diagnostically valuable material.
• Collect material from the most affected nail AND at least one additional nail if multiple nails are involved.
• Collect several nail clippings plus a good amount of subungual debris. Place clippings and debris in a clean, dry specimen bag or envelope. Do NOT place in liquid transport medium.

Scalp Scrapings and Hair (tinea capitis)

• Do NOT use antifungal shampoo (e.g., ketoconazole shampoo) for at least 3 days before collection.
• Scrape scales from the scalp surface at the edge of the affected bald or scaly patch.
• Pluck 10–12 hairs (pull from the root — infected hairs break near the scalp surface and may be short and brittle / “black dot” hairs).
• Fluorescence under Wood’s lamp may be performed first (green fluorescence = Microsporum infection; Trichophyton does NOT fluoresce). Inform the collecting physician.

Vaginal Swab (candidiasis)

• Avoid douching, vaginal medications, or intercourse for at least 24 hours before collection.
• Collected by the physician or trained nurse using a speculum — a swab of the vaginal discharge is taken and spread directly onto a clean glass slide. A Gram stain may be ordered simultaneously.

Oral Swab / Scraping (oral thrush)

• Do NOT eat or drink for 1 hour before collection.
• Do NOT use antifungal oral gel or mouthwash before collection.
• Scrape or swab the white patches on the tongue or buccal mucosa firmly enough to collect the white material.

3. What the KOH Preparation Reports

4. Reference Ranges

A positive KOH is a PRESUMPTIVE diagnosis. Culture on Sabouraud dextrose agar (SDA) is required for definitive species identification and, where applicable, antifungal susceptibility testing.

5. Factors Affecting Results

• Prior antifungal therapy (most common cause of false-negative KOH)
• Insufficient specimen quantity (inadequate scales, short nail clipping)
• Collection from the wrong area (center instead of active margin)
• Artefacts: cotton fibers, air bubbles, and cell membranes can mimic hyphae (“pseudohyphae”) — experienced microscopy is required
• Inadequate KOH digestion time or concentration (too dilute = cells not cleared; too concentrated = specimen disintegrates)
• Delay in examination after KOH application causes specimen over-digestion
• Very superficial or chronic lesions may have very low fungal burden

This guide is for informational purposes only and does not constitute medical advice. All results must be interpreted by the attending physician in the context of the patient’s clinical history, symptoms, and other diagnostic findings.

Immunoserology & Microbiology

Quick Reference & Reminders

Immunoserology and microbiology at a glance · general reminders

1. Immunoserology at a Glance

2. Microbiology at a Glance

3. General Reminders

1. For all serology tests: inform the laboratory of all current medications, supplements (especially biotin for thyroid tests), recent vaccinations, blood transfusions, and underlying conditions.
2. For HIV testing: written informed consent is legally required before collection. No exceptions. Confidentiality is strictly maintained under RA 11166.
3. For all tumor markers: an elevated result is NOT a diagnosis of cancer and a normal result does NOT rule it out. Results must be interpreted by your physician.
4. For microbiology specimens: collect BEFORE starting antibiotic or antifungal therapy whenever possible. Prior treatment is the single most common cause of false-negative microbiology results.
5. Label all specimens clearly with full name, date, and time of collection before submitting to the laboratory.
6. Results will be available within the turnaround time specified for each test. MACE Diagnostic Center will notify you when results are ready for pickup or release to your physician.

This guide is for informational purposes only and does not constitute medical advice. All results must be interpreted by the attending physician in the context of the patient’s clinical history, symptoms, and other diagnostic findings.