Medical Laboratory Technician Exam Laboratory Operations and QC 5

Question 1

Which of the following is the BEST indicator that a pipette is in need of recalibration?

Accepted Answer

QC results show a sudden positive shift across multiple analytes

Answer

A sudden positive shift in multiple analytes often points to a volumetric error such as a pipette delivering too much sample.

Question 2

Carryover in automated analyzers refers to:

Accepted Answer

Contamination of a sample by residual material from a previous sample

Answer

Carryover occurs when residual material from a prior sample contaminates the next sample, falsely affecting its result.

Question 3

A laboratory is comparing results from a new method to an established reference method. The best statistical tool to evaluate proportional bias is:

Accepted Answer

Passing-Bablok regression

Answer

Passing-Bablok regression evaluates agreement between two methods and can detect both constant and proportional bias.

Question 4

A spectrophotometer reads a standard solution that should have 0.400 absorbance but displays 0.398. This difference is an example of:

Accepted Answer

Random error only

Answer

A single small deviation from the expected value is consistent with random (imprecision) error rather than a consistent systematic bias.

Question 5

In laboratory quality management, 'total allowable error' (TEa) defines:

Accepted Answer

The maximum error acceptable for a test to be clinically useful

Answer

TEa is the maximum permissible combination of imprecision and inaccuracy for a test result to remain clinically meaningful.

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