a point or two between the certificate and an independent result is inside what two labs disagree by, i could be wrong
#test-results 2025-07-16
Wednesday40 messages6 participantstimes are UTC
Highlights from this day
- vial_ledger — i told GGPeps about a result they would not have liked and they did not argue. credit where it is due 07:46
- vial_ledger — sample handling on your end absolutely affects it. draw cleanly, ship fast, do not let it sit warm 11:09
- vial_ledger — how do you separate batch variance from supplier variance 11:18
weigh the vial before you reconstitute. it costs nothing and catches the common failure
test it again
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i have never regretted spending the money on a test. i have regretted not testing twice, ask me again in a month
i told GGPeps about a result they would not have liked and they did not argue. credit where it is due
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post the lot, the purchase month, the lab, the number, and what you were expecting. that makes it useful later
my sheet has 9 lots from CPC with a spread under a point, which is tight
is a purity-only test worth the money if underfill is the common failure
On this day 4 years ago this channel logged 60 messages.
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for the archive do you test every order or sample it
do the results in this channel skew because people test when suspicious
one bad test does not condemn a supplier. one good test does not clear one. both halves get ignored equally
i had a result i am fairly sure was a handling error on my side and i logged it as such
thats not great
a result without a lot number and a purchase date is an anecdote with a pdf attached
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the results in this channel skew because people test when they are suspicious. that is selection bias and it is real
log the boring results too. a channel that only records failures produces a false picture, your mileage will differ
thats a fill problem
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a single sample tells you about a single vial. that is genuinely all it tells you
one data point
attach the pdf
nice result
[edited]a supplier disputing a result is rare here and it has never gone well for the supplier, ymmv
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i test roughly every tenth vial. it is a sampling strategy, not paranoia, i could be wrong
98.1 against a certificate of 99 is fine. the same supplier landing low four times in a row is a question
| 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 |
update on the earlier thing underfill is more common than impurity. if you only test purity you are testing the less likely failure
my vial assayed under label but the purity was fine, which matters more
| 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 |
my read after three years of this: purity is mostly fine across the market and fill consistency is where suppliers differ
slightly off topic but anyone had a result they think was a lab error rather than a bad vial
sample handling on your end absolutely affects it. draw cleanly, ship fast, do not let it sit warm
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if you are testing to settle an argument you will not settle it with n of 1
how do you separate batch variance from supplier variance
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if the vial has been through a bad transit you are testing the transit as much as the supplier
log the boring ones
when did you buy it
weigh it first
is quantity testing available as a separate thing or bundled
how many lots do you need before you can say anything about a supplier
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selection bias
whats the lot
[edited]