MCQ on Clinical Biochemistry and Diagnostic Tests

🟢 EASY (1–20)

1. Which of the following is commonly used to assess blood glucose levels?
   a) ALT
   b) Creatinine
   c) Glucose oxidase test ✅
   d) Bilirubin
   Explanation: The glucose oxidase method is specific for glucose.
2. What is the normal range of fasting blood glucose in mg/dL?
   a) 40–60
   b) 70–100 ✅
   c) 100–120
   d) 150–200
   Explanation: Values above 100 indicate impaired fasting glucose or diabetes.
3. Which enzyme is elevated in liver damage?
   a) Amylase
   b) Lipase
   c) ALT ✅
   d) Creatine kinase
   Explanation: ALT (alanine aminotransferase) rises in liver injury.
4. Which test is commonly used to assess kidney function?
   a) Troponin
   b) Serum creatinine ✅
   c) AST
   d) Glucose
   Explanation: Creatinine levels indicate glomerular filtration efficiency.
5. Which marker is used for diagnosing myocardial infarction?
   a) Bilirubin
   b) Troponin ✅
   c) ALT
   d) ALP
   Explanation: Cardiac troponins are released when heart muscle is damaged.
6. The test used to measure long-term glucose control in diabetics is:
   a) Fasting glucose
   b) Random glucose
   c) HbA1c ✅
   d) OGTT
   Explanation: HbA1c reflects average glucose over 2–3 months.
7. Which electrolyte is most abundant in extracellular fluid?
   a) Potassium
   b) Sodium ✅
   c) Calcium
   d) Magnesium
   Explanation: Sodium maintains extracellular fluid volume.
8. The color of jaundiced skin is due to elevated:
   a) Urea
   b) Bilirubin ✅
   c) Creatinine
   d) Hemoglobin
   Explanation: Bilirubin accumulates due to liver or bile duct issues.
9. A lipid profile measures:
   a) Proteins and glucose
   b) HDL, LDL, total cholesterol, triglycerides ✅
   c) Enzymes
   d) Minerals only
   Explanation: Used to assess cardiovascular risk.
10. A complete blood count (CBC) includes:
    a) Glucose and calcium
    b) Hemoglobin, WBCs, platelets ✅
    c) ALT and AST
    d) Electrolytes
    Explanation: CBC provides a profile of blood cell status.
11. The test used to assess thyroid function is:
    a) ALT
    b) TSH ✅
    c) ALP
    d) Troponin
    Explanation: TSH is the primary screening test for thyroid disorders.
12. Hyperkalemia refers to increased levels of:
    a) Sodium
    b) Calcium
    c) Potassium ✅
    d) Magnesium
    Explanation: High potassium can affect cardiac function.
13. A test that checks protein in urine is called:
    a) CBC
    b) Dipstick test ✅
    c) LFT
    d) RFT
    Explanation: The dipstick test can detect albumin or proteinuria.
14. Urea and creatinine are elevated in:
    a) Liver failure
    b) Kidney dysfunction ✅
    c) Anemia
    d) Diabetes
    Explanation: Indicate reduced renal filtration.
15. Which test is used to diagnose diabetes mellitus?
    a) LFT
    b) OGTT ✅
    c) RFT
    d) CBC
    Explanation: Oral Glucose Tolerance Test assesses glucose handling.
16. Which marker is associated with prostate cancer?
    a) CEA
    b) PSA ✅
    c) CA-125
    d) Troponin
    Explanation: PSA (Prostate Specific Antigen) is used in screening and monitoring.
17. Hypocalcemia refers to low levels of:
    a) Sodium
    b) Calcium ✅
    c) Potassium
    d) Glucose
    Explanation: Causes include vitamin D deficiency or parathyroid issues.
18. A condition of high bilirubin is known as:
    a) Anemia
    b) Jaundice ✅
    c) Sepsis
    d) Azotemia
    Explanation: It leads to yellowing of skin and eyes.
19. High levels of uric acid in blood may indicate:
    a) Diabetes
    b) Gout ✅
    c) Hemophilia
    d) Cirrhosis
    Explanation: Uric acid crystals accumulate in joints.
20. Anemia is diagnosed by checking:
    a) Platelets
    b) Hemoglobin ✅
    c) Troponin
    d) Creatinine
    Explanation: Low hemoglobin indicates anemia.

🟡 MODERATE (21–40)

21. What is the normal reference range for serum sodium (Na⁺)?
    a) 100–120 mmol/L
    b) 135–145 mmol/L ✅
    c) 150–160 mmol/L
    d) 90–110 mmol/L
    Explanation: Helps maintain fluid and acid-base balance.
22. Which component of liver function test indicates cholestasis?
    a) AST
    b) ALT
    c) ALP ✅
    d) Creatinine
    Explanation: ALP increases in bile duct obstruction.
23. Which method is used to measure serum creatinine?
    a) Biuret method
    b) Jaffe reaction ✅
    c) ELISA
    d) Flame photometry
    Explanation: Jaffe method involves reaction with picric acid.
24. Which enzyme is diagnostic for acute pancreatitis?
    a) ALT
    b) Amylase ✅
    c) AST
    d) LDH
    Explanation: Amylase and lipase are elevated in pancreatitis.
25. Which condition is indicated by low TSH and high T3/T4 levels?
    a) Hypothyroidism
    b) Hyperthyroidism ✅
    c) Euthyroid
    d) Thyroid cancer
    Explanation: Overactive thyroid suppresses TSH production.
26. Which test is specific for cardiac damage within 2–4 hours?
    a) CK-MB
    b) Troponin I ✅
    c) Myoglobin
    d) ALT
    Explanation: Troponin is highly sensitive and specific.
27. What is measured in an arterial blood gas (ABG) test?
    a) Hemoglobin
    b) CO₂, O₂, pH, bicarbonate ✅
    c) Glucose
    d) Creatinine
    Explanation: Assesses respiratory and metabolic function.
28. Which cancer is associated with CA-125?
    a) Breast
    b) Prostate
    c) Ovarian ✅
    d) Colon
    Explanation: CA-125 is a tumor marker for ovarian cancer.
29. Glycosuria indicates the presence of:
    a) Protein in urine
    b) Blood in urine
    c) Glucose in urine ✅
    d) Ketones in urine
    Explanation: Suggests diabetes or renal threshold breach.
30. Which vitamin deficiency can falsely lower calcium levels?
    a) Vitamin K
    b) Vitamin D ✅
    c) Vitamin C
    d) Vitamin B12
    Explanation: Vitamin D aids calcium absorption.
31. Which marker indicates hepatitis infection?
    a) Troponin
    b) HBsAg ✅
    c) PSA
    d) CA-19.9
    Explanation: Hepatitis B surface antigen appears in infected patients.
32. Hypernatremia can cause:
    a) Muscle cramps
    b) Hypertension ✅
    c) Diarrhea
    d) Hypoglycemia
    Explanation: Elevated sodium raises blood pressure.
33. Which electrolyte abnormality causes cardiac arrhythmia?
    a) High magnesium
    b) High potassium ✅
    c) Low sodium
    d) Low glucose
    Explanation: Potassium affects myocardial excitability.
34. What is the major buffer in blood?
    a) Hemoglobin
    b) Bicarbonate ✅
    c) Phosphate
    d) Protein
    Explanation: Maintains pH via the carbonic acid-bicarbonate system.
35. Which test is performed to check iron status?
    a) TIBC and serum ferritin ✅
    b) Calcium and phosphate
    c) LDL and HDL
    d) Troponin
    Explanation: TIBC and ferritin help diagnose anemia types.
36. Which test differentiates between bacterial and viral infection?
    a) CRP ✅
    b) HbA1c
    c) Creatinine
    d) ESR
    Explanation: C-reactive protein is elevated in bacterial infections.
37. Serum amylase and lipase are elevated in:
    a) Liver cirrhosis
    b) Pancreatitis ✅
    c) Kidney failure
    d) Hepatitis
    Explanation: Used to confirm diagnosis of pancreatitis.
38. Normal range for serum potassium:
    a) 1–2 mmol/L
    b) 3.5–5.0 mmol/L ✅
    c) 5.5–6.5 mmol/L
    d) 7.0–8.0 mmol/L
    Explanation: Important for nerve and muscle function.
39. Which test is done to evaluate protein status in blood?
    a) ALT
    b) Total protein and albumin ✅
    c) Calcium
    d) Creatinine
    Explanation: Albumin reflects liver function and nutritional status.
40. Which diagnostic test confirms COVID-19?
    a) Antibody test
    b) RT-PCR ✅
    c) CBC
    d) CRP
    Explanation: RT-PCR detects viral RNA.

🔴 HARD (41–50)

41. Which enzyme is raised in bone and liver diseases?
    a) AST
    b) ALT
    c) ALP ✅
    d) CK
    Explanation: ALP isoforms are present in both tissues.
42. Which tumor marker is elevated in colon cancer?
    a) CA-125
    b) PSA
    c) CEA ✅
    d) AFP
    Explanation: Carcinoembryonic antigen is associated with colorectal carcinoma.
43. A test that measures coagulation time is:
    a) CBC
    b) PT/INR ✅
    c) RFT
    d) TIBC
    Explanation: Prothrombin time assesses blood clotting.
44. Hemoglobin A1c reflects glycemic control over:
    a) 1 day
    b) 1 week
    c) 2–3 months ✅
    d) 6 months
    Explanation: Based on RBC lifespan.
45. Which test identifies proteinuria in early kidney disease?
    a) Random urine sugar
    b) Microalbuminuria test ✅
    c) Creatinine
    d) Uric acid
    Explanation: Detects small amounts of albumin in urine.
46. Which electrolyte imbalance leads to tetany?
    a) Hypokalemia
    b) Hypercalcemia
    c) Hypocalcemia ✅
    d) Hypernatremia
    Explanation: Causes increased nerve excitability.
47. Which organ produces C-reactive protein (CRP)?
    a) Pancreas
    b) Kidney
    c) Liver ✅
    d) Bone marrow
    Explanation: CRP is an acute-phase protein synthesized by the liver.
48. GFR is estimated using:
    a) TSH
    b) Uric acid
    c) Creatinine clearance ✅
    d) ALT
    Explanation: Glomerular Filtration Rate assesses renal function.
49. Which test is used to monitor anticoagulant therapy (heparin)?
    a) PT/INR
    b) aPTT ✅
    c) CBC
    d) ESR
    Explanation: Activated Partial Thromboplastin Time is sensitive to heparin.
50. A lipid panel includes measurement of all except:
    a) Total cholesterol
    b) HDL
    c) Creatinine ✅
    d) Triglycerides
    Explanation: Creatinine is part of renal function test, not lipid profile.