Inter-lab variability in peptide testing — July 2024

DanielChem_CHI said:

One practical note: write down what you did and when, before you need it.

This is where I part company with the consensus forming above. The counter-case has not been addressed. Somebody upthread described the situation that does not fit, and the thread moved on rather than engaging with it, which is the failure mode this board is supposed to avoid.

DanielChem_CHI said:

One practical note: write down what you did and when, before you need it.

Right, and the exception is worth naming rather than left implied, because the exception is where people get into trouble.

DanielChem_CHI said:

One practical note: write down what you did and when, before you need it.

This answered a question I did not know how to ask. Sending this to two other people who asked me the same thing last week.

Clinical perspective, offered as context rather than as advice. The honest answer is that the effect is real, the magnitude is contested, and the individual variation is larger than either. Those three things can all be true at once, and most arguments here are two people holding different parts of that.

Reporting back.

Update: the thing I was blaming turned out not to be the cause. Leaving the original post as written rather than editing it, so the mistake stays visible for whoever searches this next.