Expired reagents

Yes, Clause 6.4.9 does apply, as the expired reagents are “outside specified requirements”. The laboratory must assess whether they can be used without invalidating test method results. This is the performance risk assessment that must be done. Consider the risk. It is the Laboratory’s decision whether to spend resources on testing if the expired reagents can be used or not. It depends on the nature of the reagent and test method in terms of possible breakdown products and interferences, or perhaps the reagent will be ineffective due to other reasons.  Typically use a new batch of reagent (which is not expired) and do a comparison, running the usual QC samples plus test samples in the two batches. You will need to decide on what basis you will continue using the expired reagent as it may change with time. For example if the reagent blank, and control samples fall in the expected analytical range (pass QC) then continue using and run the batch.