Cross-section

TB-500 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 TB-500, with a class minimum gradient of 15 min, the method is a live explanation.

356 recordsmedian 99.47 %spec 98.5 %

Laboratory	Reports	Gradient	MS resolution	Median purity %	Published bias (pp)	Bias-adjusted	Method suitability
Janoshik	178	30min	High	99.53	+0.00	99.53	ADEQUATE
PeptideMeter	59	28min	High	99.44	-0.05	99.49	ADEQUATE
Medutest	39	25min	Unit	99.70	+0.08	99.62	ADEQUATE
VendorInvestigate	34	32min	High	99.00	-0.11	99.11	ADEQUATE
Nordanalyt	28	35min	High	99.69	+0.02	99.67	ADEQUATE
Kestrel	18	15min	Unit	99.48	+0.24	99.24	ADEQUATE

Figure. TB-500 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.