In the world of laboratory medicine with a lot of focus on molecular assays, it’s nice to see an article on the quality of basic clinical chemistry. In the January issue of Clinical Chemistry (subscription required) an article shows that QC doesn’t work very well for a number of assays because with a reagent change, the QC results are different than the patient results. That is, for a reagent change, QC results were compared before and after the change as were a number of patient samples (I assume it was the same patient samples). The before and after differences were then compared.
I would have liked to see another control with the same experiment conducted without changing reagent lots, just to confirm that differences between QC and patients wouldn’t be observed here as well.
I suspect that the study was performed – BTW the first author Greg Miller is the president elect of AACC – because of experience that things didn’t look right upon reagent changes. For the one assay for which raw data was supplied, this looks like the case.
So with CMS’s new regulation that allows for reduction in the frequency of QC, it seems more prudent to make sure that QC is doing what it’s supposed to do.