Cross-section

LL-37 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 LL-37, with a class minimum gradient of 15 min, the method is a live explanation.

36 recordsmedian 98.61 %spec 96.5 %

Laboratory	Reports	Gradient	MS resolution	Median purity %	Published bias (pp)	Bias-adjusted	Method suitability
Janoshik	19	30min	High	98.46	+0.00	98.46	ADEQUATE
PeptideMeter	6 n=6	28min	High	98.16	-0.05	98.21	ADEQUATE
Medutest	3 n=3	25min	Unit	99.23	+0.08	99.15	ADEQUATE
Nordanalyt	3 n=3	35min	High	98.63	+0.02	98.61	ADEQUATE
Kestrel	3 n=3	15min	Unit	99.93	+0.24	99.69	ADEQUATE
VendorInvestigate	2 n=2	32min	High	98.06, 97.68	-0.11	—	ADEQUATE

Figure. LL-37 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.