one data point
#test-results 2026-04-07
Tuesday38 messages7 participantstimes are UTC
Highlights from this day
- HPLC_Hank — i told CPC about a result they would not have liked and they did not argue. credit where it is due 22:58
- HPLC_Hank — coming back to this a point or two between the certificate and an independent result is inside what two labs disagree by, still working it out 23:19
- taper_tess — coming back after 13 months with a follow up result, where do i put it 23:43
ok so a result without a lot number and a purchase date is an anecdote with a pdf attached, someone check my working
which lab
quick one a supplier disputing a result is rare here and it has never gone well for the supplier
update on the earlier thing certificate said 98.6 and the independent came back 98.1, is that a problem
whats the underfill rate people are actually seeing
anyone tested the same lot twice at different labs
how do you post a result so it is actually useful to somebody in a year
posting my PeptideMeter result on lot A-2418, what do people make of it
my sheet has 5 lots from QSC with a spread under a point, which is tight
update on the earlier thing i have never regretted spending the money on a test. i have regretted not testing twice
🧪2
selection bias
[edited]test it again
does anyone log the negative results, the boring ones
how do you separate batch variance from supplier variance
weigh the vial before you reconstitute. it costs nothing and catches the common failure
i told CPC about a result they would not have liked and they did not argue. credit where it is due
nice result
assay under label with good purity means you got less of the right thing. that is a fill problem, not a synthesis problem, happy to be corrected
is a purity-only test worth the money if underfill is the common failure
one bad test does not condemn a supplier. one good test does not clear one. both halves get ignored equally
thats within range
if you are testing to settle an argument you will not settle it with n of 1
i had a result i am fairly sure was a handling error on my side and i logged it as such, thats one data point
my result contradicts the supplier certificate, do i tell them
😂6🙏1
the widest spread in my data is about 2.6 percentage points across five lots from one supplier
the results in this channel skew because people test when they are suspicious. that is selection bias and it is real
a single sample tells you about a single vial. that is genuinely all it tells you
coming back to this a point or two between the certificate and an independent result is inside what two labs disagree by, still working it out
📉1✅1🤝14
thats a fill problem
thats not great
🤝7📉7
log the boring results too. a channel that only records failures produces a false picture
how many lots do you need before you can say anything about a supplier
i test roughly every tenth vial. it is a sampling strategy, not paranoia
genuine question quantity testing is usually a separate line item and it is the one worth paying for
coming back after 13 months with a follow up result, where do i put it
97.4 against a certificate of 99.2 is fine. the same supplier landing low four times in a row is a question
log the boring ones