The report format the maintainers ask for, and why each field is there — what changed since

post #14 is right about the mechanism and I think understates the practical bit.

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.

Worth separating two things that post #12 runs together.

Temporal patterns: if results from a supplier were good two years ago but have deteriorated recently, that is information. If they have been consistent over years, that is also information.

I disagree with the reply above, and I think the disagreement is substantive rather than terminological.

The distinction being drawn does not survive when you look at the published data for this specific question. I would be glad to be shown wrong on this, because the version I am arguing against is more convenient.

Blind submission is worth the effort: have someone else relabel the sample so neither you nor the laboratory knows which supplier it came from until the result is back. Blind results change minds; self-selected results do not.

post #18 answers the question as asked. The question underneath it is different.

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.

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.

Date the report: when the analysis was done matters. Material can degrade in storage. A report from two years ago is still useful but is not evidence about the current state of the same supplier's stock.

What "verified" means on our pages: specific lots were independently measured on stated dates by named services and results were consistent with the supplier's documentation. It is not a recommendation and does not extend to untested lots.

I read post #21 twice before replying, because I had assumed the opposite.

Disputed records: when a result disagreed and was not explained, the record says disputed and stays that way. We do not remove inconvenient history; we document it.

This follows post #21 rather than contradicting it.

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.

Lot matching: confirm the lot number on the certificate matches the lot number on the vial. A result from a different lot is not evidence about your vial.

Temporal patterns: if results from a supplier were good two years ago but have deteriorated recently, that is information. If they have been consistent over years, that is also information.

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.

Picking up post #25: that is the part I would want checked first.

For anyone arriving from a search: the marked solution above is the direct answer, and the replies underneath it add the caveats that make it safe to use.

Worth separating two things that post #25 runs together.

Dosing and purity: a vial that is 99% pure might contain 80% of its label claim if the other mass is water, counter-ion, and excipient. Purity and content are different. Both matter for different reasons.

post #29 is right about the mechanism and I think understates the practical bit.

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.