Quality Control and Quality Assessment
What this domain tests
Quality control (QC) and quality assessment (QA) test whether the laboratory detects error before and after results are released. Expect questions on control frequency, manufacturer instructions, records, and the QA program.
Core rules
- QC must follow the manufacturer's instructions; if none are provided, the laboratory must define acceptable QC.
- Many quantitative tests require at least two control levels on each day of testing, but the exact requirement depends on the test system and manufacturer.
- Equivalent quality control (EQC) may allow reduced QC only when the laboratory meets the manufacturer's criteria and validates the approach.
- QA is broader than QC: it covers preanalytic, analytic, and postanalytic processes, including specimen labeling, test ordering, PT, competency, complaints, and result reporting.
- The director must be involved in QA review.
Worked example
A chemistry analyzer's package insert requires two levels of control daily. On weekends, staff run one level to save time. Reasoning: this is a QC deviation. The second level is part of the manufacturer's required protocol, so patient results from those runs are not supported unless the laboratory takes corrective action, documents it, and reestablishes acceptable QC.
Traps
Treating QA and QC as synonyms. Using expired or improperly stored controls. Accepting out-of-range QC without investigation. Assuming EQC is automatic. Failing to document corrective action.