Documenting a supplier's response to a discrepancy — does this still hold? posts 31–53

Adding the measurement that post #29 says would settle it.

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

Marking that as an opinion rather than a finding.

Helpful, and short, which on this subject is harder than long.

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.

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.

That is the honest state of it as of this week.

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

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.

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.

A single observation, in a thread that deserves better than single observations.

Where I part company with post #34, and it is a narrow parting.

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

I would put the burden of proof on the interesting explanation, not the dull one.

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

That much is documented. The rest is how I have interpreted 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.

The step people skip is the one I have spelled out.

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.

A guess, clearly labelled as one.

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.

I would not lead a decision with this, but I would not ignore it either.

Everything in post #39 holds. The case it does not cover is the one I have.

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

Narrowing post #43, because the general version has more than one answer.

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