CLT Clinical Chemistry & Biochemical Analysis 1 — Questions and Answers
Question 1: Which enzyme is most commonly measured to assess liver cell damage (hepatocellular injury)?
- Alkaline phosphatase (ALP)
- Alanine aminotransferase (ALT) (Correct answer)
- Gamma-glutamyl transferase (GGT)
- Amylase
Correct answer: Alanine aminotransferase (ALT)
ALT is predominantly found in liver cells and is highly specific for hepatocellular injury, making it the primary marker for liver damage.
Question 2: A patient's serum glucose result is 52 mg/dL. Which condition does this value indicate?
- Hyperglycemia
- Diabetes mellitus
- Hypoglycemia (Correct answer)
- Euglycemia
Correct answer: Hypoglycemia
Hypoglycemia is defined as blood glucose below 70 mg/dL; a value of 52 mg/dL clearly falls into this range.
Question 3: Which specimen tube is most appropriate for serum chemistry panels?
- Lavender top (EDTA)
- Green top (heparin)
- Red or gold top (SST) (Correct answer)
- Blue top (citrate)
Correct answer: Red or gold top (SST)
Red or gold (SST) tubes allow blood to clot and yield serum after centrifugation, which is the standard specimen for most serum chemistry panels.
Question 4: The Jaffe reaction is used in the clinical laboratory to measure which analyte?
- Urea nitrogen
- Creatinine (Correct answer)
- Uric acid
- Total protein
Correct answer: Creatinine
The Jaffe reaction involves creatinine reacting with alkaline picrate to form an orange-red complex that is measured colorimetrically.
Question 5: Which lipoprotein is considered cardioprotective and is often called 'good cholesterol'?
- Very low-density lipoprotein (VLDL)
- Low-density lipoprotein (LDL)
- High-density lipoprotein (HDL) (Correct answer)
- Chylomicrons
Correct answer: High-density lipoprotein (HDL)
HDL transports cholesterol from peripheral tissues back to the liver for excretion, a process associated with reduced cardiovascular risk.
Question 6: A serum sodium value of 128 mEq/L would be reported as which electrolyte abnormality?
- Hypernatremia
- Hyponatremia (Correct answer)
- Hyperkalemia
- Hypokalemia
Correct answer: Hyponatremia
The normal serum sodium range is 136–145 mEq/L; a value of 128 mEq/L is below this range, indicating hyponatremia.
Question 7: In a glucose tolerance test (GTT), which two-hour post-load plasma glucose value is diagnostic of diabetes mellitus according to ADA criteria?
- ≥126 mg/dL
- ≥140 mg/dL
- ≥200 mg/dL (Correct answer)
- ≥180 mg/dL
Correct answer: ≥200 mg/dL
The ADA defines a 2-hour post-load plasma glucose of ≥200 mg/dL during an OGTT as diagnostic of diabetes mellitus.
CLT Clinical Chemistry & Biochemical Analysis 1
Which enzyme is most commonly measured to assess liver cell damage (hepatocellular injury)?