Clinical Chemistry Flashcards

Which specimen is preferred for most clinical chemistry tests to avoid interference from cellular components?

Answer: Serum or plasma separated from cells

Serum or plasma is preferred for most clinical chemistry tests because cellular components can interfere with analyte measurement and enzymatic reactions.

A patient's serum glucose is measured at 350 mg/dL. Which method is considered the reference method for glucose measurement in clinical laboratories?

Answer: Hexokinase method

The hexokinase method is considered the reference method for glucose measurement due to its high specificity and accuracy.

Which enzyme is most cardiac-specific and is considered the gold standard biomarker for myocardial infarction diagnosis?

Answer: Cardiac troponin I or T

Cardiac troponin I and T are the gold standard biomarkers for myocardial infarction due to their high cardiac specificity and sensitivity.

The normal anion gap range is approximately 8-12 mEq/L. Which formula correctly calculates the anion gap?

Answer: Na+ - (Cl- + HCO3-)

The anion gap is calculated as Na+ minus the sum of Cl- and HCO3-, representing unmeasured anions in plasma.

Which lipid fraction is inversely associated with cardiovascular disease risk and is often called 'good cholesterol'?

Answer: HDL cholesterol

HDL cholesterol is inversely associated with cardiovascular risk because it facilitates reverse cholesterol transport from peripheral tissues to the liver.

A serum creatinine of 2.5 mg/dL in an adult patient most likely indicates which condition?

Answer: Impaired renal function

A serum creatinine of 2.5 mg/dL exceeds the normal range (0.6-1.2 mg/dL) and indicates impaired glomerular filtration and renal dysfunction.

Which of the following is the most common cause of pseudohyperkalemia in a blood specimen?

Answer: Hemolysis of red blood cells in the specimen

Hemolysis releases intracellular potassium from red blood cells into the serum or plasma, causing falsely elevated potassium results.