coming back to this sample handling on your end absolutely affects it. draw cleanly, ship fast, do not let it sit warm
98.6 against a certificate of 99.2 is fine. the same supplier landing low four times in a row is a question
#test-results 2025-12-06
Saturday24 messages7 participantstimes are UTC
Highlights from this day
- assay_not_purity — i had a result i am fairly sure was a handling error on my side and i logged it as such 21:27
- assay_not_purity — i told QSC about a result they would not have liked and they did not argue. credit where it is due 21:30
- area_percent — my sheet has 6 lots from WXT with a spread under a point, which is tight 22:04
i had a result i am fairly sure was a handling error on my side and i logged it as such
🧊8📈1👍4
post the lot, the purchase month, the lab, the number, and what you were expecting. that makes it useful later
i told QSC about a result they would not have liked and they did not argue. credit where it is due
a supplier disputing a result is rare here and it has never gone well for the supplier
when did you buy it
underfill is more common than impurity. if you only test purity you are testing the less likely failure, take that with a pinch of salt
log the lot number
does a bad result on one lot condemn the whole supplier
if you are testing to settle an argument you will not settle it with n of 1
how much does sample handling on my end affect the number
posting my PeptideMeter result on lot B-0329, what do people make of it
my sheet has 6 lots from WXT with a spread under a point, which is tight
while im here log the boring results too. a channel that only records failures produces a false picture
what interests me is when the gap goes the same direction every time. once is noise, three times is a pattern
one data point
thats a fill problem
unrelated but the results in this channel skew because people test when they are suspicious. that is selection bias and it is real
selection bias
whats the lot
| Evidence | Counts? |
|---|---|
| Independent report, lot you bought, lot number legible | yes |
| Independent report, no lot number | no |
| Supplier certificate only | no |
| Screenshot of a report | no |
| Blinded pooled submission | yes, for the pool |
| A friend who said it was fine | no |
i test roughly every tenth vial. it is a sampling strategy, not paranoia
underfill is more common than impurity. if you only test purity you are testing the less likely failure
anyone had a result they think was a lab error rather than a bad vial
whats the underfill rate people are actually seeing
a point or two between the certificate and an independent result is inside what two labs disagree by, i could be wrong