QC testing is usually performed on artificial samples that have different known levels of analytes covering the range that practices might encounter clinically. They are usually purchased from PoCT manufacturers or other commercial sources, as third party test materials are preferable, where available.
After QC testing is conducted on the samples, QC results are recorded, then compared with the target range or acceptable window specified by the manufacturer. The PoCT manufacturer can provide a simple quality control record sheet to enter, review and analyse QC results.
Results indicate the reliability of the testing process, as follows:
- results falling within the target range are considered acceptable
- results falling outside the target range are unacceptable and may indicate a problem with the testing process.
If the results are unacceptable:
- corrective actions are required and need to be confirmed before this PoCT can be used with patients
- these actions and potential impact on patient management need to be documented (50).
An acceptable window for QC results is usually determined by the manufacturer when a PoCT device is first implemented and they may do so again when new lot numbers of QC material are introduced. It is recommended that practices can demonstrate that they have a system for implementing QC at appropriate times.