Cross-section

IGF-1 DES (1-3) 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 IGF-1 DES (1-3), with a class minimum gradient of 15 min, the method is a live explanation.

28 recordsmedian 98.53 %spec 95.0 %

Laboratory	Reports	Gradient	MS resolution	Median purity %	Published bias (pp)	Bias-adjusted	Method suitability
Janoshik	19	30min	High	98.55	+0.00	98.55	ADEQUATE
PeptideMeter	5 n=5	28min	High	98.32	-0.05	98.37	ADEQUATE
Nordanalyt	2 n=2	35min	High	97.56, 99.83	+0.02	—	ADEQUATE
Medutest	1 n=1	25min	Unit	99.93	+0.08	—	ADEQUATE
VendorInvestigate	1 n=1	32min	High	97.54	-0.11	—	ADEQUATE
Kestrel	0	15min	Unit	—	+0.24	—	ADEQUATE

Figure. IGF-1 DES (1-3) 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.