[Meta] the Janoshik rule is doing its job and people should stop complaining
the Janoshik rule is doing its job and people should stop complaining — posting the reasoning in public because a policy you cannot inspect is just a preference.
Tested three lots over a year rather than three vials from one lot. Cost the same and told me something completely different.
Sent a vial in specifically to check a supplier’s claim after a good experience. It matched. Boring result, worth logging.
Have now spent more on testing than on some of the orders. No regrets — the log is the reason I can buy without agonising.
Corrections welcome, especially the pedantic ones. Pedantry is how this board earns its reputation.
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.
[deleted]
ERP BPC, batch matched the paperwork, Medutest came back 98.1% against a claimed 97.5%. Paid for it myself, posting it because the log is only worth anything if people do.
Fourth lot from the same supplier in the log now and the band has been tight the whole way. That consistency is the actual finding.
Merged with the other thread on the same batch so the results sit together.
Inter-lab variance on this assay runs roughly a point either way, driven mostly by gradient and integration.
Disagreeing with this line: that gap is ordinary variance, not a contradiction between the lab and the certificate.
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.
I would not post that as a finding. It is a single result and the template asks you to say so.
First result I ever posted here got asked for the batch number and the claim. Fair, and my posts have been better ever since.
Careful with the trend claim. Four results over two years is a very sparse series to draw a line through.
Same. The GGPeps results have been sitting in a tight band across lots, which is the useful shape.
Not convinced by the comparison. Different services, different gradients, and you are treating one as ground truth.
Disagree that this is a discrepancy. 99.0% against a claimed 98.5% is inside ordinary inter-lab variance in either direction.
This. The trend across separate lots is the number that tells you about a process rather than a vial.
Do you have the trace, or only the summary?
Kept every report as a PDF with the batch in the filename. Two years in, it is the most useful folder I own.
Did the vial lot match the paperwork lot?
Cosigning on saying who paid. It is the whole basis on which this log is worth anything.
Agreed — the template exists because a result without the batch and the claim is unanchored.
Correction: that is the claimed figure, and the measured one is the higher of the two in your own screenshot.
Which service, and did you pay for it yourself?
That reading assumes area percent and net peptide content are the same number. They are not, and the report says which it is.
A series across separate lots estimates a process. Repeat tests on one lot estimate the measurement. Both are useful and they answer different questions.
What was the claim on the certificate you are comparing against?
Split one vial between Janoshik and Medutest. The two numbers were within half a point of each other and I stopped worrying about which lab to trust.
A series across separate lots estimates a process.
clara_weiss is right that the band matters more than the peak. Consistency across lots is the finding.
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.
Push back: three tests on one lot is one lot. It tells you about that lot and almost nothing about the next one.
Yes — date of analysis, because a result from two years ago describes a different manufacturing month.
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.
- 1Inter-lab variance on this assay runs roughly a point either way, driven…6 comments in this branch · started by u/tuva_kirchner