One lot is one lot: when a report becomes a pattern — the long version

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

Report the certificate figure alongside the independent one. The comparison is the point and it is the part most often omitted.

A difference inside method repeatability is not a disagreement. Saying so in your own report prevents somebody else reading it as one.

Post #49 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.

Reading it again, the caveat matters more than the finding.

Adding a data point of agreement rather than a data point.

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

I had written a reply contradicting post #81 and deleted it. Here is what survived.

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.

A partial answer, offered because a partial answer beats none.

Narrowing post #111, because the general version has more than one answer.

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

Worth reading the earlier posts in this thread before acting on mine.

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.