This is a continuation of a long topic, addressed by post number rather than by page. Start at post 1.
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.
That is all the detail I have. Someone else will have more.
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.
I would put a moderate confidence on that and no more.
Thank you — that answers what I came here to find out.
Post #123 is right about the mechanism and I think understates the practical bit.
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 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.
The honest answer is that it depends, and here is what it depends on.
Do not adjust a reported figure. Post what the laboratory said and put your interpretation in a separate sentence.
This is where my knowledge stops and I would rather mark the edge than blur 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.
Post #126 put the caveat in the right place and I want to underline it.
Include the sample handling: how it was stored, how it travelled to the laboratory, how long it sat. A result on badly handled material is measuring the handling.
Post #129 answers the question as asked. The question underneath it is different.
Reports of ordinary results are more valuable than reports of remarkable ones, precisely because only the remarkable ones get posted elsewhere.
The general answer and the answer for your case may diverge here.
Report the certificate figure alongside the independent one. The comparison is the point and it is the part most often omitted.
Recording a reorder result against the original is one of the highest-value contributions here, because consistency over time is what a single result cannot show.
Reports of ordinary results are more valuable than reports of remarkable ones, precisely because only the remarkable ones get posted elsewhere.
Where you submitted more than one vial from a consignment, say so. Intra-consignment comparison is one of the more useful things an individual can contribute.
Not disagreeing with anyone above, just adding the bit I keep having to look up.
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.
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.
It is the sort of thing that seems obvious in retrospect and was not at the time.
Building on post #142 rather than restating it.
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.
Post #140 put the caveat in the right place and I want to underline it.
One lot is one lot. It becomes a pattern at three or four, and the record is built to show which of those you are looking at.
On balance I think that is right, and I would not bet much on 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.
Written quickly, so the reasoning may be tighter than the wording.
Post #146 is the version of this I will quote in future. One addition.
Where you have no independent result, a documentation report is still worth filing: what the certificate contained, what it omitted, and how fast a request was answered.
If that reads as pedantic, it is, and it has saved me twice.
Coming back to post #149, because the follow-up matters more than the original answer.
The maintainers will ask for missing fields rather than rejecting a report. Filling them in afterwards is normal and nobody minds.
That is the shape of it. The detail is where I would expect to be corrected.