ok so a result without a lot number and a purchase date is an anecdote with a pdf attached
#test-results 2025-09-21
Sunday57 messages10 participantstimes are UTC
Highlights from this day
- verify_or_dont — the results in this channel skew because people test when they are suspicious. that is selection bias and it is real if you are testing to settle an argument you will… 22:27
- underfill_uma — do you test every order or sample it 22:49
- declared_value — 96.8 against a certificate of 99.4 is fine. the same supplier landing low four times in a row is a question 23:18
- declared_value — underfill is more common than impurity. if you only test purity you are testing the less likely failure 23:43
attach the pdf
a point or two between the certificate and an independent result is inside what two labs disagree by
post the lot, the purchase month, the lab, the number, and what you were expecting. that makes it useful later
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the honest limits: hobby chain of custody is weak and any result here should be read with that in mind
| 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 |
underfill is more common than impurity. if you only test purity you are testing the less likely failure
which lab
log the boring results too. a channel that only records failures produces a false picture, take that with a pinch of salt
test it again
[edited]the widest spread in my data is about 2.6 percentage points across five lots from one supplier
ok so anyone had a result they think was a lab error rather than a bad vial
if you are testing to settle an argument you will not settle it with n of 1
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does anyone log the negative results, the boring ones
whats the worst result anyone has logged and what happened next
Verification log updated: SSA — evidence added, status unchanged.
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
coming back to this assay under label with good purity means you got less of the right thing. that is a fill problem, not a synthesis problem, from memory
nice result
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certificate said 99.4 and the independent came back 99, is that a problem
[edited]the results in this channel skew because people test when they are suspicious. that is selection bias and it is real
if you are testing to settle an argument you will not settle it with n of 1
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 / 10mgupdate from 17 months ago: retested the same supplier, result came back better, logged both, take that with a pinch of salt
if the vial has been through a bad transit you are testing the transit as much as the supplier
i told QST about a result they would not have liked and they did not argue. credit where it is due
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i test roughly every tenth vial. it is a sampling strategy, not paranoia
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selection bias
log the lot number
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 / 10mgthats not great
quantity testing is usually a separate line item and it is the one worth paying for
a single sample tells you about a single vial. that is genuinely all it tells you
is anyone tracking results over time in a way they would share
how do you separate batch variance from supplier variance
my sheet has 2 lots from TFC with a spread under a point, which is tight
do you test every order or sample it
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my read after three years of this: purity is mostly fine across the market and fill consistency is where suppliers differ
a supplier disputing a result is rare here and it has never gone well for the supplier
thats a fill problem
log the boring ones
one bad test does not condemn a supplier. one good test does not clear one. both halves get ignored equally
which lab
i told HJ about a result they would not have liked and they did not argue. credit where it is due
anyone tested the same lot twice at different labs
a supplier disputing a result is rare here and it has never gone well for the supplier
weigh the vial before you reconstitute. it costs nothing and catches the common failure, thats just me
whats the lot
when did you buy it
i have never regretted spending the money on a test. i have regretted not testing twice
weigh it first
how many lots do you need before you can say anything about a supplier
thats within range
| 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 |
96.8 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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sample handling on your end absolutely affects it. draw cleanly, ship fast, do not let it sit warm
update on the earlier thing do the results in this channel skew because people test when suspicious
posting my VendorInvestigate result on lot A-2601, what do people make of it
has a supplier ever disputed a result posted here
when did you buy it
when did you buy it
what interests me is when the gap goes the same direction every time. once is noise, three times is a pattern
one data point, someone check my working
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underfill is more common than impurity. if you only test purity you are testing the less likely failure
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