Documenting a supplier's response to a discrepancy

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.

If this contradicts something upthread, the upthread version may well be the better one.

Photograph the vial and the label before opening. It costs ten seconds and it is what turns a report into something checkable.

The part I am sure of is shorter than the part I have written.

Understood. Thank you for being specific about the limits of it.

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

Do not adjust a reported figure. Post what the laboratory said and put your interpretation in a separate sentence.

The cost of a submission is worth stating. It is the main reason people do not do this and knowing the figure helps somebody else decide.

That is all I can say without guessing.

Post #19 is right about the mechanism and I think understates the practical bit.

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.

I would rather say I do not know than round it up to an answer.

Following this. I have the same question and no better information than the first post.

Reports of ordinary results are more valuable than reports of remarkable ones, precisely because only the remarkable ones get posted elsewhere.

Speaking for myself and not for anyone else who has posted here.

Picking up post #20: that is the part I would want checked first.

Photograph the vial and the label before opening. It costs ten seconds and it is what turns a report into something checkable.

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.

Written in the hope of being told what I have missed.

Reports of ordinary results are more valuable than reports of remarkable ones, precisely because only the remarkable ones get posted elsewhere.

Adding the caveat now so it does not have to be extracted later.

Do not adjust a reported figure. Post what the laboratory said and put your interpretation in a separate sentence.

Noting that I have skin in this question and have tried to discount for it.

This follows post #24 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.

Noted, and thank you for writing it out rather than summarising it.

Post #27 answers the question as asked. The question underneath it is different.

The cost of a submission is worth stating. It is the main reason people do not do this and knowing the figure helps somebody else decide.

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.