Splitting a vial for two laboratories: how to do it without ruining both posts 61–71

Where I part company with post #59, and it is a narrow parting.

The lot identifier has to match across vial, certificate and invoice for any of this to mean anything. It is the floor and it is worth checking every time.

Post #59 is the version of this I will quote in future. One addition.

Posting my splitting a vial numbers with the method attached so they can be discounted properly. Uncontrolled, unblinded, and collected by someone who wanted a particular answer.

That is a cleaner way of putting what I was circling around.

I had written a reply contradicting post #62 and deleted it. Here is what survived.

Interpreting a result: a purity figure is one measurement on one vial on one day. Agreement across two services is much stronger. A single high number does not establish a pattern.

The four services answer different questions. A documentation review cannot tell you what is in a vial and a purity assay cannot tell you whether the records are internally consistent.

For what it is worth, the same held on the two occasions I checked.

The record shows what was measured. Everything beyond that is inference and this site tries to keep the line visible.

A guess, clearly labelled as one.

Picking up post #67: that is the part I would want checked first.

Careful with the language on splitting a vial. "Not detected" and "not present" are different findings and the first is a statement about the method.

Following, with nothing to contribute beyond having asked the same thing elsewhere.

Verification records are dated because they expire in usefulness. A result from two years ago describes a lot from two years ago.

Correct me on the arithmetic if it is wrong; I would rather know.

I changed my mind about splitting a vial after someone here asked me for the source and I could not produce one. That is worth saying out loud because it is the ordinary way it happens.