if you are testing to settle an argument you will not settle it with n of 1
#test-results 2026-04-13
Monday55 messages11 participantstimes are UTC
Highlights from this day
- adelaide_assay — does a bad result on one lot condemn the whole supplier 18:01
- tyne_tracks — sorry to jump in the results in this channel skew because people test when they are suspicious. that is selection bias and it is real 18:18
- appetite_back — quick one certificate said 96.8 and the independent came back 98.6, is that a problem 19:05
- split_dose_sam — quick one 97.4 against a certificate of 99.4 is fine. the same supplier landing low four times in a row is a question 19:17
- split_dose_sam — quick one my vial assayed under label but the purity was fine, which matters more 19:32
slightly off topic but do the results in this channel skew because people test when suspicious
sorry to jump in my read after three years of this: purity is mostly fine across the market and fill consistency is where suppliers differ
i had a result i am fairly sure was a handling error on my side and i logged it as such, for what its worth
has a supplier ever disputed a result posted here
ok so how do you separate batch variance from supplier variance
quantity testing is usually a separate line item and it is the one worth paying for
how many lots do you need before you can say anything about a supplier
does a bad result on one lot condemn the whole supplier
| 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 |
coming back to this i have never regretted spending the money on a test. i have regretted not testing twice, your mileage will differ
when did you buy it
unrelated but my sheet has 2 lots from WXT with a spread under a point, which is tight
if the vial has been through a bad transit you are testing the transit as much as the supplier
sorry to jump in 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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sorry to jump in one bad test does not condemn a supplier. one good test does not clear one. both halves get ignored equally
genuine question post the lot, the purchase month, the lab, the number, and what you were expecting. that makes it useful later
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*VendorInvestigate not the other one
log the boring results too. a channel that only records failures produces a false picture, i have it written down somewhere
do you test every order or sample it
i told SGN about a result they would not have liked and they did not argue. credit where it is due
how much does sample handling on my end affect the number
whats the underfill rate people are actually seeing
quick one certificate said 96.8 and the independent came back 98.6, is that a problem
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*PeptideMeter not the other one
is it worth testing if the vial has already been through a warm transit
right so weigh the vial before you reconstitute. it costs nothing and catches the common failure
log the lot number
quick one 97.4 against a certificate of 99.4 is fine. the same supplier landing low four times in a row is a question
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thats not great
is anyone tracking results over time in a way they would share
quick one my vial assayed under label but the purity was fine, which matters more
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a point or two between the certificate and an independent result is inside what two labs disagree by, i think
what interests me is when the gap goes the same direction every time. once is noise, three times is a pattern
96.8 against a certificate of 98.6 is fine. the same supplier landing low four times in a row is a question
the widest spread in my data is about 2.6 percentage points across five lots from one supplier, i think
update from 22 months ago: retested the same supplier, result came back better, logged both
underfill is more common than impurity. if you only test purity you are testing the less likely failure
a result without a lot number and a purchase date is an anecdote with a pdf attached
a supplier disputing a result is rare here and it has never gone well for the supplier, i think
weigh it first
sample handling on your end absolutely affects it. draw cleanly, ship fast, do not let it sit warm, for what its worth
for the archive how do you post a result so it is actually useful to somebody in a year
[edited]anyone had a result they think was a lab error rather than a bad vial
selection bias
the honest limits: hobby chain of custody is weak and any result here should be read with that in mind
does anyone log the negative results, the boring ones
nice result
anyone tested the same lot twice at different labs
thats within range
[edited]one data point
thats a fill problem
a single sample tells you about a single vial. that is genuinely all it tells you
one data point
posting my Medutest result on lot SG-1177, what do people make of it
i test roughly every tenth vial. it is a sampling strategy, not paranoia