Laboratory Science Clinical Chemistry 2

Question 1

Which electrolyte imbalance is most commonly associated with cardiac arrhythmias?

Accepted Answer

Hypokalemia or hyperkalemia

Answer

Both hypokalemia and hyperkalemia alter the cardiac action potential, leading to potentially life-threatening arrhythmias; potassium is the most critical electrolyte for cardiac rhythm.

Question 2

What does an anion gap calculation help identify?

Accepted Answer

Cause of metabolic acidosis (distinguishing gap from non-gap acidosis)

Answer

Anion gap = Na⁺ − (Cl⁻ + HCO₃⁻); an elevated gap suggests accumulation of unmeasured anions (lactate, ketones, toxins), distinguishing high-gap from normal-gap metabolic acidosis.

Question 3

Which pancreatic enzyme is elevated in acute pancreatitis and peaks within 24 hours of onset?

Accepted Answer

Amylase (rises faster but falls sooner)

Answer

Serum amylase rises within 2–12 hours of acute pancreatitis onset and peaks within 24 hours, though lipase is more specific and remains elevated longer.

Question 4

What is the Henderson-Hasselbalch equation used for in clinical chemistry?

Accepted Answer

Relating blood pH to bicarbonate and dissolved CO₂ concentration

Answer

The Henderson-Hasselbalch equation (pH = pKa + log[HCO₃⁻/0.0307×pCO₂]) describes the relationship between pH, bicarbonate, and CO₂, critical for interpreting acid-base disorders.

Question 5

Elevated serum bilirubin causing jaundice can be differentiated into pre-hepatic, hepatic, and post-hepatic types by measuring:

Accepted Answer

Direct (conjugated) vs. indirect (unconjugated) bilirubin fractions

Answer

Direct (conjugated) hyperbilirubinemia suggests hepatic or post-hepatic obstruction, while indirect (unconjugated) hyperbilirubinemia suggests pre-hepatic hemolysis or Gilbert syndrome.

Laboratory Science Practice Test

Laboratory Science Practice Test

Laboratory Science Clinical Chemistry 2