The more information one has, the easier it is to identify the cause of a QC problem. Data logs such as the dates and extent of instrument calibration, reagent lot changes, and other factors that might affect the assay must be maintained. Then to troubleshoot, find the date when the problem first appeared from the QC charts and try to match it to something from the procedure logs. For example, if a shift happened following calibration, recalibrate the assay to see if the original mean is regained. It is vitally important that all pertinent information is maintained in a data log and that QC charts are actively reviewed.
Early intervention can forestall more serious problems later.
The laboratory must have a written plan to follow when equipment malfunctions or a QC problem is identified, precluding the reporting of patients' results. As with much of CLIA, documentation is the key. If it is not written down, it did not happen. If QC limits established by the director are compromised, patient test results in the unacceptable run or since the last acceptable test run must be evaluated and remedial action must be taken to ensure the reporting of only accurate and reliable results. Although CLIA requires that controls be run only once a day, controls should be run more frequently for high volume tests.