Cross-section

Leuprolide 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 Leuprolide, with a class minimum gradient of 15 min, the method is a live explanation.

28 recordsmedian 99.01 %spec 98.5 %

Laboratory	Reports	Gradient	MS resolution	Median purity %	Published bias (pp)	Bias-adjusted	Method suitability
Janoshik	9	30min	High	98.43	+0.00	98.43	ADEQUATE
PeptideMeter	6 n=6	28min	High	99.13	-0.05	99.18	ADEQUATE
Medutest	4 n=4	25min	Unit	99.86	+0.08	99.78	ADEQUATE
Nordanalyt	4 n=4	35min	High	99.19	+0.02	99.17	ADEQUATE
VendorInvestigate	3 n=3	32min	High	98.90	-0.11	99.01	ADEQUATE
Kestrel	2 n=2	15min	Unit	99.93, 99.82	+0.24	—	ADEQUATE

Figure. Leuprolide 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.