[Meta] proposal — a flair for Medutest posts
Proposal, not a decision: proposal — a flair for Medutest posts.
If the report gives a mass spectrum as well as UV purity, say so. Identity and relative quantity are separate claims and the log tracks both.
Date of analysis anchors the result to a manufacturing period. A two-year-old result is evidence about two years ago and should be read that way.
Chain of custody is why member-funded testing is worth more than a supplied certificate: the vial tested is the vial that arrived at a member’s door.
Happy to answer the boring questions. Those are usually the ones worth asking.
best — the order this archive was captured in
Inter-lab variance on this assay runs roughly a point either way, driven mostly by gradient and integration. Two results inside that band agree; they do not disagree quietly.
How to build a series that means something, if you are going to spend money on testing anyway.
Three tests on one lot tells you about your measurement. Three tests on three lots, spread over a year, tells you about a process. The second is the one worth paying for and it costs the same.
Buy small, keep the batch numbers, send one vial per lot, and post each one with the claim next to it. After four or five you have something no individual review can give you: a band, a direction and a date range. That is what the source pages are made of.
a result with no batch number is about a vial nobody can identify
What was the claim on the certificate you are comparing against?
That reading assumes area percent and net peptide content are the same number. They are not, and the report says which it is.
the log is cumulative, that is the whole value of it
Tested three lots over a year rather than three vials from one lot. Cost the same and told me something completely different.
Yes. Two services on the same batch is the strongest thing an individual member can produce, and it is not expensive.
A series across separate lots estimates a process. Repeat tests on one lot estimate the measurement. Both are useful and they answer different questions.
The template is vendor, compound, batch, service, claim, result, and who paid. Every one of those fields exists because a result missing it has been argued about here before.
area percent unless the report says otherwise
Right, and a point or two between services is ordinary. It is agreement, and every month somebody posts it as a scandal.
Retitled — the original stated a discrepancy the numbers do not show.
Retitled — the original stated a discrepancy the numbers do not show.
Agreed — and two services on one batch is the strongest thing any of us can produce individually.
How many separate lots does your series cover?
Agreed — the template exists because a result without the batch and the claim is unanchored.
Not convinced by the comparison. Different services, different gradients, and you are treating one as ground truth.
Which service, and did you pay for it yourself?
Kept every report as a PDF with the batch in the filename. Two years in, it is the most useful folder I own.
post the claim next to the result or the number floats
Split one vial between PeptideMeter and VendorInvestigate. The two numbers were within half a point of each other and I stopped worrying about which lab to trust.
vendor, compound, batch, service, result — that is the template
That service reports area percent by default. Worth stating, since the thread has been comparing it to a mass figure.
On inter-lab disagreement, which generates more heat here than anything else.
Two services running different gradients, integrating differently, at possibly different wavelengths, will not produce identical numbers on the same material. A point either way is ordinary. Half a point is close agreement.
The productive response to a gap that size is to post both results with both methods and let the log accumulate. The unproductive response is to pick the lower number, call it the truth, and open a dispute. Members have done the first for long enough now that the bands in the vendor tables are genuinely informative.
- 1Right, and a point or two between services is ordinary. It is agreement, and…9 comments in this branch · started by u/milan_villalobos