log the lot number
#test-results 2025-04-13
Sunday52 messages10 participantstimes are UTC
Highlights from this day
- split_dose_sam — anyone tested the same lot twice at different labs 15:28
- lot_number_lou — has a supplier ever disputed a result posted here 16:06
- split_dose_sam — underfill is more common than impurity. if you only test purity you are testing the less likely failure 17:40
- blind_submit — coming back to this the results in this channel skew because people test when they are suspicious. that is selection bias and it is real 18:26
- gradient_greg — quantity testing is usually a separate line item and it is the one worth paying for 19:09
weigh the vial before you reconstitute. it costs nothing and catches the common failure
thats within range
how do you separate batch variance from supplier variance
how many lots do you need before you can say anything about a supplier
log the boring ones
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selection bias
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coming back to this i had a result i am fairly sure was a handling error on my side and i logged it as such
anyone tested the same lot twice at different labs
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if you are testing to settle an argument you will not settle it with n of 1
i told CPC about a result they would not have liked and they did not argue. credit where it is due
do the results in this channel skew because people test when suspicious
nice result
which lab
[edited]does a bad result on one lot condemn the whole supplier
is a purity-only test worth the money if underfill is the common failure
my read after three years of this: purity is mostly fine across the market and fill consistency is where suppliers differ
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thats not great
[edited]a single sample tells you about a single vial. that is genuinely all it tells you
follow up is it worth testing if the vial has already been through a warm transit
a supplier disputing a result is rare here and it has never gone well for the supplier
*Medutest not the other one
how much does sample handling on my end affect the number
a supplier disputing a result is rare here and it has never gone well for the supplier
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
sample handling on your end absolutely affects it. draw cleanly, ship fast, do not let it sit warm
posting my VendorInvestigate result on lot SG-1177, what do people make of it
update from 20 months ago: retested the same supplier, result came back better, logged both
a point or two between the certificate and an independent result is inside what two labs disagree by
unrelated but assay under label with good purity means you got less of the right thing. that is a fill problem, not a synthesis problem
update from 7 months ago: retested the same supplier, result came back better, logged both
one bad test does not condemn a supplier. one good test does not clear one. both halves get ignored equally
my vial assayed under label but the purity was fine, which matters more
test it again
underfill is more common than impurity. if you only test purity you are testing the less likely failure
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whats the worst result anyone has logged and what happened next
thats a fill problem
my sheet has 8 lots from SGN with a spread under a point, which is tight
i test roughly every tenth vial. it is a sampling strategy, not paranoia
if the vial has been through a bad transit you are testing the transit as much as the supplier
Recon calculator: 15mg in 5ml = 4mg/ml.
the widest spread in my data is about 2.6 percentage points across five lots from one supplier
update from 21 months ago: retested the same supplier, result came back better, logged both
weigh it first
99.4 against a certificate of 99 is fine. the same supplier landing low four times in a row is a question, n of 1 obviously
i have never regretted spending the money on a test. i have regretted not testing twice
[edited]coming back to this the results in this channel skew because people test when they are suspicious. that is selection bias and it is real
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when did you buy it
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attach the pdf
a result without a lot number and a purchase date is an anecdote with a pdf attached
is anyone tracking results over time in a way they would share
quantity testing is usually a separate line item and it is the one worth paying for
| 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 |