A report I filed that turned out to be wrong, and the correction

A report I filed that turned out to be wrong, and the correction Writing it up because I had to work it out twice and would rather nobody else did.

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

• Compound: tirzepatide
• Independent testing: Janoshik
• Method as reported: reversed-phase HPLC, 214 nm
• Result: 97.8% area
• Certificate figure for the same lot: 98.3%

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.

Marking my place. If it changes for me I will come back and say so.

I had written a reply contradicting the opening post and deleted it. Here is what survived.

Comparing your result to somebody else's on a different lot is not a comparison of suppliers. Lot is the unit and it should be in every report.

The maintainers will ask for missing fields rather than rejecting a report. Filling them in afterwards is normal and nobody minds.

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

I have seen it go both ways, which is why I hedge.

This follows post #5 rather than contradicting it.

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.

The short answer was in the first line; everything after is the working.

The format we ask for is compound, lot, testing service, method as reported, result, and the certificate figure for the same lot. A report missing any of those goes to the discussion rather than the record.

This is where my knowledge stops and I would rather mark the edge than blur it.

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

Anyone with a larger sample, please post it.

Nothing to add, except that this is the answer I would give if asked.

Taking post #8 at face value and following it one step further.

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

The arithmetic in post #10 is right; the assumption feeding it is the part to check.

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.

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.

Reading rather than answering, but this is the post I would point somebody at.

Post #12 put the caveat in the right place and I want to underline it.

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.

It is the sort of thing that seems obvious in retrospect and was not at the time.