Cross-section

GHRP-6 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 GHRP-6, with a class minimum gradient of 15 min, the method is a live explanation.

169 recordsmedian 99.65 %spec 99.0 %

Laboratory	Reports	Gradient	MS resolution	Median purity %	Published bias (pp)	Bias-adjusted	Method suitability
Janoshik	108	30min	High	99.70	+0.00	99.70	ADEQUATE
PeptideMeter	19	28min	High	99.25	-0.05	99.30	ADEQUATE
Nordanalyt	14	35min	High	99.55	+0.02	99.53	ADEQUATE
VendorInvestigate	12	32min	High	99.22	-0.11	99.33	ADEQUATE
Medutest	11	25min	Unit	99.90	+0.08	99.82	ADEQUATE
Kestrel	5 n=5	15min	Unit	99.93	+0.24	99.69	ADEQUATE

Figure. GHRP-6 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.