genuine question i test roughly every tenth vial. it is a sampling strategy, not paranoia, for what its worth
#test-results 2026-04-04
Saturday49 messages9 participantstimes are UTC
Highlights from this day
when did you buy it
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if you are testing to settle an argument you will not settle it with n of 1
assay under label with good purity means you got less of the right thing. that is a fill problem, not a synthesis problem
post the lot, the purchase month, the lab, the number, and what you were expecting. that makes it useful later
whats the underfill rate people are actually seeing
update from 21 months ago: retested the same supplier, result came back better, logged both
i have never regretted spending the money on a test. i have regretted not testing twice
my sheet has 6 lots from ERP with a spread under a point, which is tight
is it worth testing if the vial has already been through a warm transit
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how much does sample handling on my end affect the number
thats within range
attach the pdf
genuine question how many lots do you need before you can say anything about a supplier
selection bias
log the boring ones
log the lot number
sorry to jump in the widest spread in my data is about 2.6 percentage points across five lots from one supplier
thats not great
coming back after 24 months with a follow up result, where do i put it
whats the lot
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whats the worst result anyone has logged and what happened next
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weigh the vial before you reconstitute. it costs nothing and catches the common failure
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weigh it first
what interests me is when the gap goes the same direction every time. once is noise, three times is a pattern
unrelated but sample handling on your end absolutely affects it. draw cleanly, ship fast, do not let it sit warm
if the vial has been through a bad transit you are testing the transit as much as the supplier
a supplier disputing a result is rare here and it has never gone well for the supplier, i think
nice result
[edited]coa-kp-0925.pdf
1 page · 479 KB · not retained in the public archive
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i had a result i am fairly sure was a handling error on my side and i logged it as such
underfill is more common than impurity. if you only test purity you are testing the less likely failure
test it again
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slightly off topic but one bad test does not condemn a supplier. one good test does not clear one. both halves get ignored equally
log the boring results too. a channel that only records failures produces a false picture
99 against a certificate of 99.4 is fine. the same supplier landing low four times in a row is a question
*Medutest not the other one
anyone had a result they think was a lab error rather than a bad vial
thats a fill problem
weigh the vial before you reconstitute. it costs nothing and catches the common failure
does anyone log the negative results, the boring ones
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i told Homopeptide about a result they would not have liked and they did not argue. credit where it is due
the honest limits: hobby chain of custody is weak and any result here should be read with that in mind, i think
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certificate said 99.4 and the independent came back 98.6, is that a problem
a single sample tells you about a single vial. that is genuinely all it tells you
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is a purity-only test worth the money if underfill is the common failure
is anyone tracking results over time in a way they would share
a point or two between the certificate and an independent result is inside what two labs disagree by
do you test every order or sample it
| 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 |
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if the vial has been through a bad transit you are testing the transit as much as the supplier