It is important, if not imperative, that new lots of reagents and calibrators be tested before being put on line. This should be done with replicates of the controls (3-4 each) and 6-8 patients, new reagent side by side with the current reagents or calibrators. Measure the average of the difference means and compare the total error (TE) before and after the possible change. Another statistic is the Student t-test that will detect a difference between the means. However it does not give as much information about TE as does the average or % bias. We suggest using just the means and % bias. Keep in mind that QC is the best error detector once the method has been validated. It is worthwhile to compare TE and TEa and then select the best rule(s) for detecting errors (thus reducing risks).
The Lab and Risk Reduction, Part 6