1. Check your reagents and controls.
- Verify that all lot numbers and expiration dates of reagents and controls used in the testing process are current.
- Verify that the recommended storage conditions were followed. (Not only the material was placed in the proper storage location, but this location has been monitored for proper performance and temperature.)
In addition:
- New lots of QC material should always be run in parallel with the old lot number - before being used for analysis. This may also be referred to as a crossover study. This type of study is performed by testing the existing QC lot (before the current QC lot runs out or expires) alongside or parallel to the new lot of QC material. This is done to establish new QC ranges. A defined number of runs must take place before calculating the new range for the new lot. It is possible that the new lot number was placed in use and this is the reason for the out-of-control results.
- Keep a check on water quality (as some QC material requires the addition of laboratory-grade water to the lyophilized material). Perhaps the lab water source has become contaminated due to poor maintenance.
- Monitor glassware and pipettes for proper calibration checks. Perhaps the pipettor is broken and does not measure correctly. (Remember, these items may be used by the laboratory worker when preparing QC material.)
- Also ask: Did the laboratory worker prepare the QC material properly? (Proper training? Training documentation? Competency checks performed?)
