Bioequivalence and Bioavailability Forum

Hi everyone,
I've been trying to develop an SOP for pk repeats and wanted to ask the forum about a few issues. In general, repeats are not recommended but may be warranted if suspected problems in the clinic (sample switching) or physiologically implausible data are shown. To identify an anomalous value, I want to build in 2 checks:

1. test the anomalous value against the expected value within that subject through interpolation - check if they differ by >xx%,
2. test the anomalous value against the corresponding value in other subjects - check if the anomalous is different from other subjects.

Both 1) and 2) must be fulfilled (ie: significantly different) in order for a sample re-analysis to be issued.

My first question is does anyone have any suggestions on how to do the second check? I'm thinking to derive a range for that value across subjects from the 25-75th percentile and check if the anomalous value falls outside this range.

Moving forward, if re-analysis is issued and the re-analysed value is within xx% of the original anomalous value (ie: confirmed), it can be dropped from the stats analysis. If it is outside xx%, the re-analysed value (or mean of these values assuming they were re-analysed in duplicate) will be used in the analysis - and hope the results don't change too much.

In either case, the stats analysis would need to be presented with both the anomalous value and without (or with the re-analysed values).

My second question is does this sound like a valid approach? Or am I out in left field ?

Thanks,
sciguy