Cross-section

ARA-290 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 ARA-290, with a class minimum gradient of 15 min, the method is a live explanation.

65 recordsmedian 99.45 %spec 98.0 %

Laboratory	Reports	Gradient	MS resolution	Median purity %	Published bias (pp)	Bias-adjusted	Method suitability
Janoshik	25	30min	High	99.42	+0.00	99.42	ADEQUATE
PeptideMeter	12	28min	High	99.59	-0.05	99.64	ADEQUATE
VendorInvestigate	10	32min	High	98.75	-0.11	98.86	ADEQUATE
Medutest	9	25min	Unit	99.81	+0.08	99.73	ADEQUATE
Nordanalyt	6 n=6	35min	High	99.70	+0.02	99.69	ADEQUATE
Kestrel	3 n=3	15min	Unit	99.74	+0.24	99.50	ADEQUATE

Figure. ARA-290 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.