thats not great
#test-results 2025-09-29
Monday41 messages12 participantstimes are UTC
Highlights from this day
- batch_bandit — a point or two between the certificate and an independent result is inside what two labs disagree by 15:21
- batch_bandit — a single sample tells you about a single vial. that is genuinely all it tells you 15:56
- batch_bandit — underfill is more common than impurity. if you only test purity you are testing the less likely failure 15:57
- no_appetite_nia — i test roughly every tenth vial. it is a sampling strategy, not paranoia 16:15
what interests me is when the gap goes the same direction every time. once is noise, three times is a pattern
Inter-lab diff for lot E-2205: 99.4% vs 99.2%. Within expected range.
attach the pdf
post the lot, the purchase month, the lab, the number, and what you were expecting. that makes it useful later
a point or two between the certificate and an independent result is inside what two labs disagree by
lot bought purity assay/label
A-2418 2025-03 99.1% 9.6 / 10mg
A-2601 2025-08 98.7% 9.8 / 10mg
B-0114 2026-01 99.3% 9.4 / 10mg
B-0329 2026-04 98.9% 9.9 / 10mg👀7
weigh it first
update from 16 months ago: retested the same supplier, result came back better, logged both
assay under label with good purity means you got less of the right thing. that is a fill problem, not a synthesis problem
sample handling on your end absolutely affects it. draw cleanly, ship fast, do not let it sit warm
a single sample tells you about a single vial. that is genuinely all it tells you
👍1📈9
underfill is more common than impurity. if you only test purity you are testing the less likely failure
🔥7❤️1📈13
log the lot number
🎉2🤝2
log the boring ones
[edited]how do you separate batch variance from supplier variance
i told HJ about a result they would not have liked and they did not argue. credit where it is due
if the vial has been through a bad transit you are testing the transit as much as the supplier
slightly off topic but is quantity testing available as a separate thing or bundled
whats the lot
i test roughly every tenth vial. it is a sampling strategy, not paranoia
🧊10🔥18
thats within range
test it again
ok so if the vial has been through a bad transit you are testing the transit as much as the supplier
quantity testing is usually a separate line item and it is the one worth paying for
*VendorInvestigate not the other one
my read after three years of this: purity is mostly fine across the market and fill consistency is where suppliers differ
98.6 against a certificate of 99.2 is fine. the same supplier landing low four times in a row is a question
nice result
[edited]how much does sample handling on my end affect the number
is a purity-only test worth the money if underfill is the common failure
selection bias
which lab
my sheet has 3 lots from FGP with a spread under a point, which is tight
i have never regretted spending the money on a test. i have regretted not testing twice
a supplier disputing a result is rare here and it has never gone well for the supplier
one data point
if you are testing to settle an argument you will not settle it with n of 1
if you are testing to settle an argument you will not settle it with n of 1
a result without a lot number and a purchase date is an anecdote with a pdf attached
i had a result i am fairly sure was a handling error on my side and i logged it as such
[edited]coming back after 11 months with a follow up result, where do i put it
anyone had a result they think was a lab error rather than a bad vial
one bad test does not condemn a supplier. one good test does not clear one. both halves get ignored equally