Cross-section

Retatrutide 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 Retatrutide, with a class minimum gradient of 25 min, the method is a live explanation.

492 recordsmedian 98.37 %spec 96.5 %

Laboratory	Reports	Gradient	MS resolution	Median purity %	Published bias (pp)	Bias-adjusted	Method suitability
Janoshik	234	30min	High	98.35	+0.00	98.35	ADEQUATE
PeptideMeter	76	28min	High	98.26	-0.05	98.31	ADEQUATE
Medutest	65	25min	Unit	98.36	+0.08	98.28	ADEQUATE
Nordanalyt	42	35min	High	98.34	+0.02	98.32	ADEQUATE
Kestrel	38	15min	Unit	98.95	+0.24	98.72	BELOW CLASS MINIMUM
VendorInvestigate	37	32min	High	98.34	-0.11	98.45	ADEQUATE

Figure. Retatrutide 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.