Reproducibility, measured rather than assumed
The Journal submitted split samples from single lots to three assay services, under names unconnected to this publication, and published each method alongside each result.
Testing Dispatch
Independent analysis puts a SWB tirzepatide lot at 98.3%, against 95.6% on the certificate
The report states the gradient, the wavelength and the integration threshold, which is more than most.
Two laboratories analysing vials from the same tirzepatide lot have returned figures 1.1 percentage points apart. VendorInvestigate reported 98.3%; Medutest reported a lower number on a shallower gradient with a tighter integration threshold. Both results are defensible and the difference is entirely methodological, which is the point of publishing them together.
The Journal purchased 8 vials from the same lot at retail and had four of them analysed separately, in order to distinguish vial-to-vial variation from method variation. Vial-to-vial agreement was within 0.4 percentage points. Method-to-method disagreement was an order of magnitude larger.
The Journal purchased 8 vials from the same lot at retail and had four of them analysed separately, in order to distinguish vial-to-vial variation from method variation. Vial-to-vial agreement was within 0.4 percentage points. Method-to-method disagreement was an order of magnitude larger.
Batch variance rather than vendor quality is the recurring finding of this programme. Across the 13 determinations the Journal has commissioned to date, within-vendor spread has been wider than between-vendor spread for two thirds of the companies tracked, which is an argument against rating any supplier on a single number.
Dr Emiko Tanabe, mass spectrometrist, wanted the wavelength printed. "A method reading at 280 nanometres cannot see a fragment that has lost its aromatic residue. That is not a failure of the laboratory, it is a fact about the question they were asked."SWB’s dossier has been updated with this determination and with the company’s response to it. The dossier’s ordering box records the lead times, the minimum quantities and what a buyer should ask for at the point of order.
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Documentation practice is the only part of vendor quality a buyer can assess before purchase.
Who signed this, and what did they undertake by signing it
Somebody has to be answerable for a release document. On most certificates in this market, nobody is named at all.
Who signed this, and what did they undertake by signing it
Two signatures — one who performed the work, one who approved its release — are the ordinary regulated convention and are almost unknown here.
The badge is about a sample. The listing is about a product.
Every step between the laboratory report and the product page removes information, and the badge is the last step.