Calibration verification is not the same as calibration. Calibration verification is the process of testing prepared samples of known concentration in the same way as patient samples to confirm that the instrument's calibration throughout the reportable range is within acceptable analytical criteria. This is a CLIA regulatory requirement and must be performed every six months (or more frequently if specified in the manufacturer’s instructions).
Calibration verification may also be necessary or useful to perform when:
- Major preventive maintenance or replacement of critical components of the analytical system has occurred.
or
- Control materials reflect an unusual trend, shift, or fall outside acceptable limits and other means of assessing and correcting unacceptable control values fail to identify and correct the problem.
Calibration verification is not required when:
- The analytical system has a calibration procedure that includes three or more calibration levels, including a low, mid, and high value AND is performed at least once every six months.
- Testing utilizes automated chemistry analyzers AND the laboratory routinely tests at least three levels of quantitative QC spanning the reportable range of the assay.
- Testing uses automated cell counters; calibration verification is not required if the laboratory follows all manufacturer instructions.
- The testing performed is non-quantitative (e.g., Coagulation Testing such as Prothrombin Time (PT) which is measured in units of time).
- Instruments are manufacturer-calibrated.
