AssayIndex
Cross-section

P21 by laboratory

The same compound measured by different laboratories on different gradients. Where the medians differ, the question is whether the material differed or the method did — and for P21, with a class minimum gradient of 15 min, the method is a live explanation.

4 recordsmedian 99.19 %spec 98.0 %
LaboratoryReportsGradientMS resolutionMedian purity %Published bias (pp)Bias-adjustedMethod suitability
Medutest2 n=225minUnit99.83, 98.88+0.08—ADEQUATE
Nordanalyt2 n=235minHigh99.13, 99.26+0.02—ADEQUATE
Janoshik030minHigh—+0.00—ADEQUATE
PeptideMeter028minHigh—-0.05—ADEQUATE
VendorInvestigate032minHigh—-0.11—ADEQUATE
Kestrel015minUnit—+0.24—ADEQUATE
98.899.099.299.499.599.799.9MedutestMedutest: Q1 99.12, median 99.35, Q3 99.59, n=2n=2NordanalytNordanalyt: Q1 99.16, median 99.19, Q3 99.23, n=2n=2 Purity (% area)
Figure. P21 purity by contributing laboratory. Any offset between rows has two possible sources — a real difference in the material each laboratory happened to receive, and the laboratory's own bias — and this figure cannot separate them. The paired analysis that can is on inter-lab agreement.