Potential or confirmed failures in assay performance can be frustrating to identify and repair. Sometimes troubleshooting is as simple as repeating QC, but assay failures can escalate rapidly to the point of needing to stop all testing, sending specimens to a reference laboratory, and/or significantly repairing or replacing an instrument. Calibration and recalibration analysis are central to these determinations. In many circumstances, the best strategy will involve considering the simplest solutions to the failure first, followed by more complex (typically more difficult to diagnose and repair) solutions further down the troubleshooting cascade.
The following is a stepwise approach to troubleshooting QC/calibration/reagent failures. Some steps may not make sense based on an individual scenario.
- Review QC plots and identify any concerning drifts, shifts, or other abnormal characteristics.
- Review expiration dates of all reagents, QC, and calibration material.
- Verify no major instrument failures or maintenance occurred within the timeframe of concern.
- Attempt reanalysis with fresh QC.
- New and unopened QC material is best
- Attempt reanalysis with new QC from a different lot (if available).
- Attempt recalibration with fresh calibrator and reanalyze QC.
- New and unopened calibrator material is best
- Attempt recalibration with new calibrator material from a different lot (if available).
- Escalate to Laboratory Supervisor, Director, and/or Manufacturer for the next steps.
