Cross-section

Humanin (HNG) 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 Humanin (HNG), with a class minimum gradient of 15 min, the method is a live explanation.

42 recordsmedian 99.47 %spec 97.5 %

Laboratory	Reports	Gradient	MS resolution	Median purity %	Published bias (pp)	Bias-adjusted	Method suitability
Janoshik	23	30min	High	99.45	+0.00	99.45	ADEQUATE
Medutest	7 n=7	25min	Unit	99.64	+0.08	99.56	ADEQUATE
PeptideMeter	5 n=5	28min	High	99.46	-0.05	99.51	ADEQUATE
Nordanalyt	5 n=5	35min	High	99.47	+0.02	99.45	ADEQUATE
VendorInvestigate	1 n=1	32min	High	99.71	-0.11	—	ADEQUATE
Kestrel	1 n=1	15min	Unit	99.14	+0.24	—	ADEQUATE

Figure. Humanin (HNG) 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.