attach the pdf
#test-results 2025-10-19
Sunday51 messages10 participantstimes are UTC
Highlights from this day
- spare_vial — i told WXT about a result they would not have liked and they did not argue. credit where it is due 16:40
- HPLC_Hank — has a supplier ever disputed a result posted here log the boring results too. a channel that only records failures produces a false picture 17:30
- blank_run — underfill is more common than impurity. if you only test purity you are testing the less likely failure 18:04
- spare_vial — my sheet has 6 lots from ERP with a spread under a point, which is tight 20:32
- spare_vial — is anyone tracking results over time in a way they would share 20:35
98.6 against a certificate of 99.2 is fine. the same supplier landing low four times in a row is a question
if the vial has been through a bad transit you are testing the transit as much as the supplier
selection bias
one data point
posting my VendorInvestigate result on lot B-0114, what do people make of it
assay under label with good purity means you got less of the right thing. that is a fill problem, not a synthesis problem
weigh it first
[edited]🎉17
anyone had a result they think was a lab error rather than a bad vial
i told WXT about a result they would not have liked and they did not argue. credit where it is due
weigh the vial before you reconstitute. it costs nothing and catches the common failure
coming back to this i have never regretted spending the money on a test. i have regretted not testing twice
the widest spread in my data is about 2.6 percentage points across five lots from one supplier
what interests me is when the gap goes the same direction every time. once is noise, three times is a pattern
log the boring ones
Reminder for spare_vial: dose day is today. Set 8 days ago.
do the results in this channel skew because people test when suspicious
has a supplier ever disputed a result posted here
log the boring results too. a channel that only records failures produces a false picture
📉13
does anyone log the negative results, the boring ones
my result contradicts the supplier certificate, do i tell them
one bad test does not condemn a supplier. one good test does not clear one. both halves get ignored equally
which lab
the results in this channel skew because people test when they are suspicious. that is selection bias and it is real
📉1
quick one my vial assayed under label but the purity was fine, which matters more
underfill is more common than impurity. if you only test purity you are testing the less likely failure
| 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 |
unrelated but a single sample tells you about a single vial. that is genuinely all it tells you
*that should say weekly
anyone tested the same lot twice at different labs
i test roughly every tenth vial. it is a sampling strategy, not paranoia
a result without a lot number and a purchase date is an anecdote with a pdf attached
[redacted at member request] · archive policy
whats the lot
a point or two between the certificate and an independent result is inside what two labs disagree by
Inter-lab diff for lot A-2601: 99.2% vs 98.6%. Within expected range.
whats the worst result anyone has logged and what happened next
post the lot, the purchase month, the lab, the number, and what you were expecting. that makes it useful later
a supplier disputing a result is rare here and it has never gone well for the supplier
when did you buy it
the honest limits: hobby chain of custody is weak and any result here should be read with that in mind
quantity testing is usually a separate line item and it is the one worth paying for
my sheet has 6 lots from ERP with a spread under a point, which is tight
how much does sample handling on my end affect the number
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is anyone tracking results over time in a way they would share
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 / 10mgthats a fill problem
coming back after 26 months with a follow up result, where do i put it
my read after three years of this: purity is mostly fine across the market and fill consistency is where suppliers differ
if you are testing to settle an argument you will not settle it with n of 1
log the lot number
follow up sample handling on your end absolutely affects it. draw cleanly, ship fast, do not let it sit warm, thats just me