Laboratory Science Clinical Chemistry 1 — Questions and Answers
Question 1: What is the reference range for fasting blood glucose in a non-diabetic adult?
- 40–70 mg/dL
- 70–99 mg/dL (Correct answer)
- 120–150 mg/dL
- 160–200 mg/dL
Correct answer: 70–99 mg/dL
Normal fasting plasma glucose is 70–99 mg/dL; values of 100–125 mg/dL indicate prediabetes, and ≥126 mg/dL on two occasions diagnoses diabetes mellitus.
Question 2: Which enzyme is the primary cardiac biomarker used to diagnose acute myocardial infarction?
- ALT (alanine aminotransferase)
- Troponin I or T (Correct answer)
- Amylase
- Lipase
Correct answer: Troponin I or T
Cardiac troponin I and T are highly specific to myocardial cells; elevated levels in blood indicate cardiomyocyte necrosis and are the gold standard for diagnosing AMI.
Question 3: What does the HbA1c test measure?
- Current blood glucose at time of draw
- Average blood glucose over the past 2–3 months (Correct answer)
- Insulin secretion capacity
- Red blood cell lifespan
Correct answer: Average blood glucose over the past 2–3 months
HbA1c measures the percentage of hemoglobin glycated by glucose, reflecting average blood glucose over 2–3 months (the lifespan of RBCs), used to monitor diabetes management.
Question 4: Elevated serum creatinine is most indicative of dysfunction in which organ?
- Liver
- Pancreas
- Kidney (Correct answer)
- Thyroid
Correct answer: Kidney
Creatinine is a muscle metabolism byproduct filtered by the kidneys; elevated serum creatinine indicates reduced glomerular filtration rate (GFR) and kidney dysfunction.
Question 5: Which liver enzyme is most specific for hepatocellular damage?
- AST (aspartate aminotransferase)
- ALT (alanine aminotransferase) (Correct answer)
- GGT (gamma-glutamyl transferase)
- ALP (alkaline phosphatase)
Correct answer: ALT (alanine aminotransferase)
ALT is predominantly found in liver cells, making it more specific for hepatocellular injury than AST, which is also found in heart and skeletal muscle.
Question 6: What is the purpose of the eGFR calculation in clinical chemistry?
- Estimate liver synthetic function
- Estimate kidney filtration capacity based on creatinine, age, sex, and race (Correct answer)
- Calculate cardiac output
- Measure thyroid hormone clearance
Correct answer: Estimate kidney filtration capacity based on creatinine, age, sex, and race
eGFR (estimated Glomerular Filtration Rate) uses serum creatinine with patient variables to estimate kidney filtration capacity, staging chronic kidney disease (CKD stages 1–5).
Laboratory Science Clinical Chemistry 1
What is the reference range for fasting blood glucose in a non-diabetic adult?