Laboratory Operations, Quality Management, and Safety
Laboratory Operations, Quality Management, and Safety tests how a laboratory controls the total testing process, documents quality, and protects staff and patients. Expect questions on QC rules, proficiency testing, corrective action, biosafety, and chemical hygiene.
Core rules
- The total testing process has preanalytical, analytical, and postanalytical phases. Most errors occur before analysis: wrong tube, wrong patient, hemolysis, delayed transport.
- Quality control uses stable materials at defined intervals. Westgard rules detect random and systematic error; 1-3s and 2-2s are rejection rules, while 1-2s is usually a warning.
- Proficiency testing is external quality assessment; unacceptable results require investigation, root cause, corrective action, and effectiveness checks.
- SOPs require version control, approval, review, and training records. CAPA closes the loop from problem to prevention.
- Biosafety requires risk assessment, PPE, hand hygiene, spill kits, sharps disposal, and appropriate containment. Chemical hygiene requires labeling, SDS access, and segregation of incompatible wastes.
Worked example
A chemistry control is 2.6 SD above the mean, and the next control on the same level is 2.4 SD above the mean. Apply the 2-2s rule: reject the run because two consecutive values exceed 2 SD on the same side. Reasoning: this pattern suggests systematic error, such as calibration drift or reagent deterioration. Do not release patient results until the problem is corrected and QC passes.
Traps
Do not confuse calibration with QC; calibration sets the measuring relationship, QC verifies performance. Do not repeat only the failed control and ignore patient results already reported. Underfilled tubes and wrong anticoagulants are preanalytical errors, not instrument faults. Safety traps include recapping needles and storing bleach with acids.