CHT Laboratory Management & Safety 2 — Questions and Answers
Question 1: What is the primary purpose of running a negative control in a Luminex SAB HLA antibody assay?
- To establish baseline non-specific background fluorescence for result interpretation (Correct answer)
- To verify the positive control exceeded the MFI threshold
- To confirm bead lot number accuracy
- To test for complement activation in normal serum
Correct answer: To establish baseline non-specific background fluorescence for result interpretation
Negative controls (normal human serum or buffer) establish the background MFI level; patient MFI values must exceed this background to be considered true positive signals.
Question 2: What action should be taken when a reagent lot number changes for a critical assay in a histocompatibility laboratory?
- Perform parallel testing with the old and new lot to verify equivalent performance before clinical use (Correct answer)
- Immediately discard the old lot and begin using the new lot
- Report the lot change to the accrediting body before use
- Request a waiver from CLIA before implementing the new lot
Correct answer: Perform parallel testing with the old and new lot to verify equivalent performance before clinical use
Lot-to-lot verification ensures that the new reagent lot performs equivalently to the current lot on known samples before being used for clinical testing.
Question 3: Which document describes the step-by-step procedure for performing a test, including safety precautions, reagents, and interpretation criteria?
- Standard Operating Procedure (SOP) (Correct answer)
- Quality Management Plan (QMP)
- Laboratory Developed Test (LDT) validation report
- Corrective Action Report (CAR)
Correct answer: Standard Operating Procedure (SOP)
SOPs provide detailed, validated instructions for performing laboratory procedures consistently and are required by CLIA and accreditation standards.
Question 4: What is the significance of turnaround time (TAT) monitoring in a deceased donor histocompatibility laboratory?
- Rapid TAT is critical because organs have limited viability and allocation decisions cannot wait (Correct answer)
- TAT is only important for elective living donor workups
- TAT standards are set by individual labs with no external requirements
- TAT monitoring is only used for billing purposes
Correct answer: Rapid TAT is critical because organs have limited viability and allocation decisions cannot wait
Deceased donor typing, crossmatching, and antibody results must be reported rapidly because organ ischemia time is limited and allocation is time-critical.
Question 5: What is 'delta check' monitoring in the histocompatibility laboratory?
- Comparing a current patient result to a previous result to flag unexpected changes that may indicate an error (Correct answer)
- Checking instrument delta calibration before each run
- Comparing laboratory results to peer group means
- Monitoring room temperature changes that exceed delta thresholds
Correct answer: Comparing a current patient result to a previous result to flag unexpected changes that may indicate an error
Delta checks compare current test results against a patient's prior results; unexpected changes (e.g., new HLA allele appearing) trigger investigation for specimen mix-up or error.
Question 6: Which regulation requires clinical laboratories to maintain records for a minimum number of years to allow review and audit?
- CLIA 88 (42 CFR Part 493) record retention requirements (Correct answer)
- OSHA bloodborne pathogen standard
- FDA 21 CFR Part 820 quality system regulation
- HIPAA privacy rule minimum necessary standard
Correct answer: CLIA 88 (42 CFR Part 493) record retention requirements
CLIA requires laboratories to retain test records, quality control data, and procedural documentation for defined periods (generally 2 years for test records, longer for some categories).
CHT Laboratory Management & Safety 2
What is the primary purpose of running a negative control in a Luminex SAB HLA antibody assay?