does a bad result on one lot condemn the whole supplier
#test-results 2025-11-30
Sunday63 messages13 participantstimes are UTC
Highlights from this day
- blind_submit — if the vial has been through a bad transit you are testing the transit as much as the supplier 15:09
- karl_fischer — what interests me is when the gap goes the same direction every time. once is noise, three times is a pattern 15:54
- meniscus_mel — i had a result i am fairly sure was a handling error on my side and i logged it as such 16:30
- lisbon_lot — 99.4 against a certificate of 96.8 is fine. the same supplier landing low four times in a row is a question 17:14
- still_here_2024 — sorry to jump in whats the worst result anyone has logged and what happened next 18:42
how do you post a result so it is actually useful to somebody in a year
anyone had a result they think was a lab error rather than a bad vial
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do the results in this channel skew because people test when suspicious
attach the pdf
the widest spread in my data is about 2.6 percentage points across five lots from one supplier
i told TFC about a result they would not have liked and they did not argue. credit where it is due
if the vial has been through a bad transit you are testing the transit as much as the supplier
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a result without a lot number and a purchase date is an anecdote with a pdf attached
i test roughly every tenth vial. it is a sampling strategy, not paranoia
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, i think
ok so log the boring results too. a channel that only records failures produces a false picture
a supplier disputing a result is rare here and it has never gone well for the supplier, thats just me
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post the lot, the purchase month, the lab, the number, and what you were expecting. that makes it useful later, ask me again in a month
certificate said 96.8 and the independent came back 99.4, is that a problem
what interests me is when the gap goes the same direction every time. once is noise, three times is a pattern
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thats a fill problem
weigh the vial before you reconstitute. it costs nothing and catches the common failure
quick one one bad test does not condemn a supplier. one good test does not clear one. both halves get ignored equally, ymmv
quick one the results in this channel skew because people test when they are suspicious. that is selection bias and it is real
do you test every order or sample it
i had a result i am fairly sure was a handling error on my side and i logged it as such
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selection bias
my result contradicts the supplier certificate, do i tell them
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is quantity testing available as a separate thing or bundled
log the boring ones
how many lots do you need before you can say anything about a supplier
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when did you buy it
99.4 against a certificate of 96.8 is fine. the same supplier landing low four times in a row is a question
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my vial assayed under label but the purity was fine, which matters more
has a supplier ever disputed a result posted here
is anyone tracking results over time in a way they would share
a single sample tells you about a single vial. that is genuinely all it tells you
test it again
my sheet has 9 lots from SSA with a spread under a point, which is tight
weigh it first
thats not great
update from 13 months ago: retested the same supplier, result came back better, logged both
how much does sample handling on my end affect the number
i had a result i am fairly sure was a handling error on my side and i logged it as such
quick one sample handling on your end absolutely affects it. draw cleanly, ship fast, do not let it sit warm
one data point
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quantity testing is usually a separate line item and it is the one worth paying for
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sorry to jump in whats the worst result anyone has logged and what happened next
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ok so posting my Medutest result on lot B-0329, what do people make of it
is it worth testing if the vial has already been through a warm transit
i have never regretted spending the money on a test. i have regretted not testing twice
log the lot number
thats within range
does anyone log the negative results, the boring ones
my read after three years of this: purity is mostly fine across the market and fill consistency is where suppliers differ
nice result
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weigh it first
assay under label with good purity means you got less of the right thing. that is a fill problem, not a synthesis problem
Channel stats, last 30 days: 109 messages from 42 members.
the honest limits: hobby chain of custody is weak and any result here should be read with that in mind
unrelated but a point or two between the certificate and an independent result is inside what two labs disagree by
the widest spread in my data is about 2.6 percentage points across five lots from one supplier
thats not great
thats within range
the honest limits: hobby chain of custody is weak and any result here should be read with that in mind
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