Medical Laboratory Technician Exam Laboratory Operations and QC 4

Question 1

The Westgard 2-2s rule is triggered when:

Accepted Answer

Two consecutive controls exceed the mean by 2 SD in the same direction

Answer

The 2-2s warning rule is triggered when two consecutive QC results exceed ±2 SD on the same side, suggesting systematic error.

Question 2

Which of the following actions is MOST appropriate when a QC result violates a rejection rule before reporting patient results?

Accepted Answer

Hold patient results, identify the problem, and repeat QC

Answer

Patient results must be held until the QC problem is identified and corrective action is verified by repeat QC.

Question 3

A laboratory notices that serum potassium results are falsely elevated on specimens left at room temperature for several hours. This is due to:

Accepted Answer

Leakage of potassium from red blood cells

Answer

Red blood cells contain high intracellular potassium; prolonged contact with serum at room temperature causes leakage, elevating results.

Question 4

The term 'analytical sensitivity' in laboratory testing refers to:

Accepted Answer

The lowest detectable concentration of an analyte

Answer

Analytical sensitivity is the lowest analyte concentration reliably detected by the assay, also called the limit of detection.

Question 5

A laboratory wants to verify the manufacturer's claimed reference interval for a new analyzer. The minimum number of reference samples recommended by CLSI is:

Accepted Answer

20

Answer

CLSI EP28-A3c recommends a minimum of 20 reference individuals to verify a manufacturer's claimed reference interval.

Medical Laboratory Technician Exam Practice Test

Medical Laboratory Technician Exam Practice Test

Medical Laboratory Technician Exam Laboratory Operations and QC 4