Medical Laboratory Technician Exam Laboratory Operations and QC 3

Question 1

A new lot of QC material is being validated. The laboratory should establish the mean and SD by running the QC material at least:

Accepted Answer

20 times over multiple days

Answer

At least 20 replicates run over multiple days are recommended to establish reliable QC mean and SD values.

Question 2

Which specimen type is most appropriate for glucose testing when the sample cannot be processed within 30 minutes?

Accepted Answer

Plasma in a sodium fluoride/potassium oxalate tube

Answer

Sodium fluoride inhibits glycolysis, preserving glucose concentrations in plasma when processing is delayed.

Question 3

The linear range of an assay refers to the concentration interval over which:

Accepted Answer

The assay produces results directly proportional to analyte concentration

Answer

The linear range is the analyte concentration interval where instrument response is directly proportional to concentration.

Question 4

A laboratory receives a proficiency testing result of 'unacceptable' for a glucose analyte. The FIRST corrective action should be to:

Accepted Answer

Investigate the cause before resuming patient testing

Answer

The first step after an unacceptable PT result is root cause investigation; patient testing should be evaluated for impact.

Question 5

Which of the following is an example of a pre-analytical error?

Accepted Answer

Hemolysis caused by difficult venipuncture

Answer

Hemolysis from traumatic venipuncture occurs before the sample reaches the analyzer, making it a pre-analytical error.

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