Cross-section

BPC-157 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 BPC-157, with a class minimum gradient of 15 min, the method is a live explanation.

591 recordsmedian 99.15 %spec 98.0 %

Laboratory	Reports	Gradient	MS resolution	Median purity %	Published bias (pp)	Bias-adjusted	Method suitability
Janoshik	277	30min	High	99.13	+0.00	99.13	ADEQUATE
PeptideMeter	111	28min	High	98.94	-0.05	98.99	ADEQUATE
Medutest	80	25min	Unit	99.30	+0.08	99.22	ADEQUATE
VendorInvestigate	51	32min	High	98.79	-0.11	98.90	ADEQUATE
Kestrel	39	15min	Unit	99.61	+0.24	99.37	ADEQUATE
Nordanalyt	33	35min	High	99.36	+0.02	99.34	ADEQUATE

Figure. BPC-157 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.