MLS Quality Assurance & Standards 4

Question 1

A QC result exceeds 3 standard deviations from the mean. According to Westgard rules, this triggers which rule?

Accepted Answer

1-3s

Answer

The 1-3s Westgard rule is a rejection rule triggered when a single control value exceeds ±3 SD from the mean, indicating probable error.

Question 2

Which of the following BEST describes 'total allowable error' (TEa)?

Accepted Answer

The maximum permissible combination of bias and imprecision for an analyte

Answer

TEa defines the maximum error a method can produce and still yield clinically acceptable results, incorporating both systematic bias and random imprecision.

Question 3

Carryover in analytical instruments refers to:

Accepted Answer

Contamination of a sample by a previously analyzed high-concentration sample

Answer

Carryover occurs when residual analyte from a high-concentration specimen contaminates a subsequent sample, falsely elevating its result.

Question 4

A laboratory's glucose method has a sigma value of 6. This indicates:

Accepted Answer

The method performs near six sigma and needs minimal QC rules

Answer

A sigma value of 6 indicates excellent analytical performance (TEa is 6 SD wide), allowing simplified QC protocols with fewer control measurements.

Question 5

In a laboratory quality system, which document describes the step-by-step process for performing a specific test?

Accepted Answer

Standard operating procedure (SOP)

Answer

A standard operating procedure (SOP) provides detailed, step-by-step instructions for performing a specific test, ensuring consistency and reproducibility.

(MLS) Medical Laboratory Scientist Practice Test

(MLS) Medical Laboratory Scientist Practice Test

MLS Quality Assurance & Standards 4