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.

496 recordsmedian 98.41 %spec 96.5 %

Laboratory	Reports	Gradient	MS resolution	Median purity %	Published bias (pp)	Bias-adjusted	Method suitability
Janoshik	212	30min	High	98.51	+0.00	98.51	ADEQUATE
PeptideMeter	89	28min	High	98.30	-0.05	98.35	ADEQUATE
Medutest	70	25min	Unit	98.35	+0.08	98.27	ADEQUATE
VendorInvestigate	49	32min	High	97.89	-0.11	98.00	ADEQUATE
Nordanalyt	38	35min	High	98.34	+0.02	98.33	ADEQUATE
Kestrel	38	15min	Unit	98.99	+0.24	98.75	BELOW CLASS MINIMUM

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.