Laboratory Quality Control and Management Flashcards

In a single run, Level 1 control is at +2.3 SD and Level 2 control is at -2.4 SD. Which rule is violated, and what error does it indicate?

Answer: R-4s, random error

R-4s is violated when the gap between two controls in a run is more than 4 SD, which signals random error.

Repeated runs of a reference material give 4.1, 4.2, 4.1, and 4.2 mmol/L, but the true value is 5.0 mmol/L. How do you describe this method?

Answer: Precise but inaccurate

The results agree closely with each other (precise) but are far from the true value (inaccurate, biased).

Under CLIA, how often must calibration verification be done at minimum for most quantitative tests?

Answer: Every 6 months

CLIA requires calibration verification at least every 6 months, and also after major maintenance or reagent lot changes.

A patient's bilirubin result is above the analyzer's analytical measurement range (AMR). What should the technologist do?

Answer: Dilute the specimen with an approved diluent, re-run it, and multiply by the dilution factor

Results above the AMR are unreliable, so the sample is diluted within validated limits and the result is corrected for the dilution.

An assay has an allowable total error (TEa) of 10%, a bias of 2%, and a CV of 2%. What is its sigma metric?

Answer: 4

Sigma = (TEa - |bias|) / CV = (10 - 2) / 2 = 4.

Which of these is a preanalytical error?

Answer: Hemolysis from a traumatic venipuncture

Preanalytical errors happen before testing, such as at specimen collection, and hemolysis from a difficult draw is one example.

Under CLIA, how long must QC records and patient test records be kept at minimum?

Answer: 2 years

CLIA requires QC and test records to be kept at least 2 years, with longer periods for areas like immunohematology and pathology.