Like QC, the reagents and other consumables required to perform a clinical assay can age, degrade, or otherwise become compromised. Slow aging and degradation may manifest in QC drifts over time, whereas severe contamination or reagent swaps will show acute shifts. When fresh QC or recalibrations do not address the issue, reagent issues become a more likely scenario. Consider these questions when troubleshooting further:
- Was a new reagent lot started within the last several days?
- Sometimes lot-to-lot experiments appear to pass, but upon analysis of more QC over multiple days, it may be apparent the new lot does not actually perform as expected.
- Is the current reagent lot within expiration?
- Does the lot pack remain on the instrument, or is it removed and placed only when testing occurs?
- If the reagent packs get removed and stored elsewhere, there is more opportunity for contamination and/or reagent swaps.
If any of these scenarios appear likely, acquiring and testing with new reagents may be warranted.
