unpopular opinion: most of what gets said here about test results are guesswork
unpopular opinion: most of what gets said here about test results are guesswork. Change my mind, genuinely — I have no stake in being right about this.
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.
Kept every report as a PDF with the batch in the filename. Two years in, it is the most useful folder I own.
What a result posted here is actually worth, and how to make yours worth more.
A single figure with no batch identifier is about a vial nobody can locate. Add the batch and it becomes about a lot. Add the claimed figure from the certificate and it becomes a comparison. Add the service and the date and it becomes reproducible. Say that you paid for it yourself and it becomes independent.
Five extra fields, thirty seconds of typing, and the difference between a comment and a row in the log that will still be useful in three years.
Sceptical readings welcome. The confident ones are the ones I distrust.
best — the order this archive was captured in
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.
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.
post the claim next to the result or the number floats
a result with no batch number is about a vial nobody can identify
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.
Agreed — the template exists because a result without the batch and the claim is unanchored.
Area percent and net peptide content are different measurements and most reports give one. Quote which, or the comparison downstream is meaningless.
Split one vial between Janoshik and VendorInvestigate. The two numbers were within half a point of each other and I stopped worrying about which lab to trust.
Same. The SSA results have been sitting in a tight band across lots, which is the useful shape.
results without method are gossip with decimals
Disagree that this is a discrepancy. 97.4% against a claimed 97.0% is inside ordinary inter-lab variance in either direction.
Right, and a point or two between services is ordinary. It is agreement, and every month somebody posts it as a scandal.
That service reports area percent by default. Worth stating, since the thread has been comparing it to a mass figure.
That service reports area percent by default.
Adding the boring but useful bit: say whether you paid for it. It is the basis of the whole log.
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.
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.
priya_weiss is right that the band matters more than the peak. Consistency across lots is the finding.
Do you have the trace, or only the summary?
date of analysis matters as much as the number
Correction: that is the claimed figure, and the measured one is the higher of the two in your own screenshot.
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.
Did the vial lot match the paperwork lot?
A series across separate lots estimates a process. Repeat tests on one lot estimate the measurement. Both are useful and they answer different questions.
Cosigning on saying who paid. It is the whole basis on which this log is worth anything.
Retitled — the original stated a discrepancy the numbers do not show.
Is that the same lot as the one in the thread from last month?
Have now spent more on testing than on some of the orders. No regrets — the log is the reason I can buy without agonising.
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.
I would not post that as a finding. It is a single result and the template asks you to say so.
- 1Date of analysis anchors the result to a manufacturing period. A…7 comments in this branch · started by u/insulin_syringe_ian
- 2Split one vial between Janoshik and VendorInvestigate. The two numbers were…7 comments in this branch · started by u/due_diligence_dee