Quality Assurance and Regulatory Compliance
Regulatory framework
CLIA ’88 classifies tests as waived, moderate, or high complexity and sets requirements for certification, personnel, proficiency testing (PT), and inspections. CAP and The Joint Commission add accreditation standards. Quality management covers preanalytical, analytical, and postanalytical phases, including document control, competency assessment, and corrective action. CLIA requires competency assessment semiannually during the first year and annually thereafter for testing personnel.
QC rules
Levey–Jennings charts plot control values against SD. Westgard multirules: 1_2s is a warning; 1_3s, 2_2s, R_4s, 4_1s, and 10x are rejection rules. Calibration establishes the relationship between signal and concentration; QC verifies that the calibrated system is stable that day. PT samples must be tested as patient samples, never shared or referred to another laboratory.
Worked example
Two control levels are run. Level 1 is +2.5 SD and level 2 is +2.6 SD on the same run. This violates 2_2s: two consecutive control measurements exceed the same ±2 SD limit, indicating systematic error. Reject the run, do not report patient results, and investigate calibration, reagent lot, control lot, or temperature. Document the investigation and corrective action before resuming.
Traps
A single 1_2s is not automatic rejection; a single 1_3s is. QC material is not a calibrator, and QC passed does not prove calibration is current. Do not confuse PT with internal QC; PT evaluates accuracy against peer laboratories. Retention schedules, corrective-action records, and competency files are inspected, so missing documentation is a compliance finding even when patient results were acceptable.