Cross-section

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

576 recordsmedian 98.44 %spec 97.0 %

Laboratory	Reports	Gradient	MS resolution	Median purity %	Published bias (pp)	Bias-adjusted	Method suitability
Janoshik	271	30min	High	98.39	+0.00	98.39	ADEQUATE
PeptideMeter	104	28min	High	98.55	-0.05	98.59	ADEQUATE
Medutest	72	25min	Unit	98.63	+0.08	98.55	ADEQUATE
VendorInvestigate	49	32min	High	97.80	-0.11	97.91	ADEQUATE
Nordanalyt	46	35min	High	98.52	+0.02	98.50	ADEQUATE
Kestrel	34	15min	Unit	99.22	+0.24	98.98	BELOW CLASS MINIMUM

Figure. Tirzepatide 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.