Quality Assurance & Control Flashcards

Which describes proper unidirectional workflow in a PCR laboratory?

Answer: Reagent prep to sample prep to amplification/post-PCR, never moving backward

Personnel and materials move from clean pre-amplification areas to post-amplification areas so amplicons are not carried back.

Which solution is most commonly recommended for decontaminating PCR work surfaces of residual nucleic acids?

Answer: Freshly prepared 10% bleach followed by water or ethanol rinse

Sodium hypochlorite oxidizes and fragments DNA, while ethanol alone does not destroy nucleic acids.

How does UV irradiation of a PCR hood help prevent contamination?

Answer: It induces thymine dimers and crosslinks that make contaminating DNA non-amplifiable

UV light causes pyrimidine dimers in exposed DNA, so contaminating templates can no longer be amplified.

Under CLIA, if no proficiency testing program is available for a molecular test, the lab must verify the test's accuracy at least:

Answer: Twice per year

CLIA requires labs to verify the accuracy of tests without formal PT at least twice a year, for example by split-sample comparison.

The MIQE guidelines primarily address which aspect of PCR?

Answer: Minimum information for publishing and reporting qPCR experiments

MIQE (Minimum Information for Publication of Quantitative Real-Time PCR Experiments) standardizes qPCR reporting for transparency and reproducibility.

Why are aerosol-resistant (filter) pipette tips used in PCR setup?

Answer: They block aerosols from contaminating the pipette barrel and later samples

Filter barriers stop aerosolized nucleic acids from entering the pipette shaft, where they could cross-contaminate later reactions.

Before putting a new lot of master mix into clinical use, the lab should:

Answer: Perform lot-to-lot verification by testing it in parallel with the current lot using controls or known samples

Parallel testing confirms the new lot performs the same as the current lot before it is used for patient results.