CSMLS Clinical Chemistry Procedures Questions and Answers

Question 1

A patient's blood gas results on room air are: pH 7.25, pCO2 60 mmHg, HCO3- 24 mmol/L. Which of the following conditions is most consistent with these findings?

Accepted Answer

Respiratory acidosis

Answer

The pH is low (<7.35), indicating acidosis. The pCO2 is high (>45 mmHg), indicating a respiratory cause. The HCO3- is within the normal range (22-28 mmol/L), suggesting the acidosis is not of metabolic origin and is uncompensated. Therefore, the results are consistent with respiratory acidosis.

Question 2

A tech runs a quality control for creatinine and the result is 2 standard deviations above the mean. According to Westgard rules, what is the most appropriate first step?

Accepted Answer

Repeat the control on the same vial.

Answer

A single control value exceeding 2 standard deviations (a 1-2s rule violation) serves as a warning. The most common cause is random error. The initial step is to repeat the measurement using the same vial of control material to see if the error was random and self-corrects. If it remains out, further investigation is needed.

Question 3

Which of the following enzymes is most specific for assessing acute pancreatitis?

Accepted Answer

Lipase (LPS)

Answer

While both amylase and lipase levels rise in acute pancreatitis, lipase is considered more specific. Amylase can be elevated in other conditions (e.g., salivary gland disorders, renal failure). Lipase remains elevated for a longer period than amylase, making it more useful for diagnosis, especially if presentation is delayed.

Question 4

A patient sample for electrolyte analysis is noted to be severely hemolyzed. Which analyte would be most significantly falsely elevated?

Accepted Answer

Potassium (K+)

Answer

Potassium is the major intracellular cation. Hemolysis, the rupture of red blood cells, releases large amounts of potassium into the serum or plasma, causing a falsely elevated result that does not reflect the patient's true physiological state.

Question 5

An Oral Glucose Tolerance Test (OGTT) is performed on a non-pregnant adult. A fasting glucose of 6.8 mmol/L and a 2-hour post-load glucose of 11.5 mmol/L is obtained. According to Canadian Diabetes Association guidelines, this is indicative of:

Accepted Answer

Diabetes mellitus

Answer

A 2-hour plasma glucose value of ≥ 11.1 mmol/L during an OGTT is diagnostic for diabetes mellitus. While the fasting glucose is in the impaired fasting glucose range (6.1-6.9 mmol/L), the 2-hour value meets the criteria for a diagnosis of diabetes.

CSMLS - Canadian Society for Medical Laboratory Science Practice Test

CSMLS - Canadian Society for Medical Laboratory Science Practice Test

CSMLS Clinical Chemistry Procedures Questions and Answers