i had a result i am fairly sure was a handling error on my side and i logged it as such
#test-results 2026-03-18
Wednesday55 messages10 participantstimes are UTC
Highlights from this day
- nine_nine_one — right so whats the worst result anyone has logged and what happened next 15:43
- verify_or_dont — i test roughly every tenth vial. it is a sampling strategy, not paranoia 15:57
- mira_pins — i told ERP about a result they would not have liked and they did not argue. credit where it is due, i could be wrong 17:59
- aliquot_ada — how many lots do you need before you can say anything about a supplier 18:17
slightly off topic but does anyone log the negative results, the boring ones
how do you separate batch variance from supplier variance
how much does sample handling on my end affect the number
is anyone tracking results over time in a way they would share
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coming back after 10 months with a follow up result, where do i put it
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 / 10mgthe results in this channel skew because people test when they are suspicious. that is selection bias and it is real
sample handling on your end absolutely affects it. draw cleanly, ship fast, do not let it sit warm
genuine question do the results in this channel skew because people test when suspicious
does a bad result on one lot condemn the whole supplier
for the archive a supplier disputing a result is rare here and it has never gone well for the supplier
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98.6 against a certificate of 99.2 is fine. the same supplier landing low four times in a row is a question
if you are testing to settle an argument you will not settle it with n of 1
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while im here a point or two between the certificate and an independent result is inside what two labs disagree by
right so whats the worst result anyone has logged and what happened next
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a result without a lot number and a purchase date is an anecdote with a pdf attached, i have it written down somewhere
i test roughly every tenth vial. it is a sampling strategy, not paranoia
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what interests me is when the gap goes the same direction every time. once is noise, three times is a pattern
is it worth testing if the vial has already been through a warm transit
a single sample tells you about a single vial. that is genuinely all it tells you
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thats not great
my vial assayed under label but the purity was fine, which matters more
[edited]anyone had a result they think was a lab error rather than a bad vial
is a purity-only test worth the money if underfill is the common failure
[edited]coming back to this has a supplier ever disputed a result posted here
log the boring ones
the honest limits: hobby chain of custody is weak and any result here should be read with that in mind, take that with a pinch of salt
do you test every order or sample it
my result contradicts the supplier certificate, do i tell them
genuine question whats the underfill rate people are actually seeing
when did you buy it
genuine question if the vial has been through a bad transit you are testing the transit as much as the supplier
i told ERP about a result they would not have liked and they did not argue. credit where it is due, i could be wrong
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which lab
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how many lots do you need before you can say anything about a supplier
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if you are testing to settle an argument you will not settle it with n of 1
underfill is more common than impurity. if you only test purity you are testing the less likely failure
quick one my sheet has 6 lots from QST with a spread under a point, which is tight
selection bias
thats a fill problem
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genuine question anyone tested the same lot twice at different labs
weigh the vial before you reconstitute. it costs nothing and catches the common failure
test it again
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whats the lot
is quantity testing available as a separate thing or bundled
update from 4 months ago: retested the same supplier, result came back better, logged both
weigh it first
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
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test it again
the widest spread in my data is about 2.6 percentage points across five lots from one supplier
post the lot, the purchase month, the lab, the number, and what you were expecting. that makes it useful later
posting my Janoshik result on lot B-0114, what do people make of it
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nice result
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attach the pdf