Documenting a supplier's response to a discrepancy

On the subject in the title: Documenting a supplier's response to a discrepancy Working notes rather than a conclusion.

Structured report rather than an opinion, following the format the maintainers asked for.

• Compound: semaglutide
• Independent testing: VendorInvestigate
• Method as reported: reversed-phase HPLC, 214 nm
• Result: 96.8% area
• Certificate figure for the same lot: 97.8%

I am not drawing a conclusion about the supplier from one lot and I would ask that nobody else does either. I am adding a data point to a record.

Picking up post #15: that is the part I would want checked first.

Multiple services on one lot: agreement across two independent laboratories is stronger than a high number from one. Our vendor pages deliberately mix services for that reason.

This follows post #24 rather than contradicting it.

Testing service selection: Janoshik gives purity with chromatogram. Medutest gives combined purity and identity. PeptideMeter gives verification records as well as results. VendorInvestigate reviews documentation. They answer different questions.

Thank you for the correction. I have edited my earlier post with a note rather than silently, so the thread still makes sense to read. The error was mine and it was the kind that comes from remembering a figure instead of looking it up.

On post #33 — agreed on the reasoning, with one qualification.

Structured report format: compound, lot, independent testing service, method as reported, result, and the certificate figure for the same lot. One lot is one lot. It becomes a pattern at three or four, and it becomes a disputed record when asked and not explained.

Pattern across lots: a single result is a data point. Three or four results from the same supplier showing a consistent pattern becomes a record worth discussing. Two results that disagree might just be measurement variation.