post the lot, the purchase month, the lab, the number, and what you were expecting. that makes it useful later
#test-results 2025-11-07
Friday48 messages11 participantstimes are UTC
Highlights from this day
- HPLC_Hank — my sheet has 7 lots from QYB with a spread under a point, which is tight 18:59
- HPLC_Hank — a single sample tells you about a single vial. that is genuinely all it tells you 19:00
- HPLC_Hank — assay under label with good purity means you got less of the right thing. that is a fill problem, not a synthesis problem 19:17
- nate_nights — sorry to jump in quantity testing is usually a separate line item and it is the one worth paying for 21:15
for the archive underfill is more common than impurity. if you only test purity you are testing the less likely failure
a supplier disputing a result is rare here and it has never gone well for the supplier, your mileage will differ
is it worth testing if the vial has already been through a warm transit
📉3✅1
the honest limits: hobby chain of custody is weak and any result here should be read with that in mind
which lab
if you are testing to settle an argument you will not settle it with n of 1
if the vial has been through a bad transit you are testing the transit as much as the supplier
when did you buy it
if the vial has been through a bad transit you are testing the transit as much as the supplier
what interests me is when the gap goes the same direction every time. once is noise, three times is a pattern
has a supplier ever disputed a result posted here
one bad test does not condemn a supplier. one good test does not clear one. both halves get ignored equally
do the results in this channel skew because people test when suspicious
is quantity testing available as a separate thing or bundled
update from 26 months ago: retested the same supplier, result came back better, logged both
quick one the widest spread in my data is about 2.6 percentage points across five lots from one supplier
log the boring results too. a channel that only records failures produces a false picture
i test roughly every tenth vial. it is a sampling strategy, not paranoia
🧊1💀6👀1
is anyone tracking results over time in a way they would share
if you are testing to settle an argument you will not settle it with n of 1
my sheet has 7 lots from QYB with a spread under a point, which is tight
medutest-report-a-2601.pdf
3 pages · 98 KB · not retained in the public archive
a single sample tells you about a single vial. that is genuinely all it tells you
🔥3⚠️10
*that should say weekly
i have never regretted spending the money on a test. i have regretted not testing twice
a point or two between the certificate and an independent result is inside what two labs disagree by
i have never regretted spending the money on a test. i have regretted not testing twice
assay under label with good purity means you got less of the right thing. that is a fill problem, not a synthesis problem
❤️16
i told KP about a result they would not have liked and they did not argue. credit where it is due
test it again
fridge-thermometer.png
800 × 800 · 298 KB · not retained in the public archive
how do you separate batch variance from supplier variance
🙏13
anyone tested the same lot twice at different labs
the results in this channel skew because people test when they are suspicious. that is selection bias and it is real
my read after three years of this: purity is mostly fine across the market and fill consistency is where suppliers differ
weigh it first
thats not great, thats one data point
certificate said 98.1 and the independent came back 99.4, is that a problem
attach the pdf
thats a fill problem
📉1
weigh the vial before you reconstitute. it costs nothing and catches the common failure
which lab
underfill is more common than impurity. if you only test purity you are testing the less likely failure
selection bias
[edited]log the lot number
| 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 |
97.4 against a certificate of 96.8 is fine. the same supplier landing low four times in a row is a question, ill dig out the number
panel_before_aftera point or two between the certificate and an independent result is inside what two…
sample handling on your end absolutely affects it. draw cleanly, ship fast, do not let it sit warm
unrelated but one data point
sorry to jump in quantity testing is usually a separate line item and it is the one worth paying for
🙏1👀1🤝14
which lab
On this day 2 years ago this channel logged 138 messages.
nice result, for what its worth