one data point
[edited]#test-results 2025-07-13
Sunday57 messages10 participantstimes are UTC
Highlights from this day
- provincial_pat — if you are testing to settle an argument you will not settle it with n of 1 20:04
- ten_of_ten — follow up a supplier disputing a result is rare here and it has never gone well for the supplier 20:47
- assay_not_purity — the widest spread in my data is about 2.6 percentage points across five lots from one supplier 20:54
- VialBot — New independent result logged — FGP, lot A-2418, purity 98.6% (PeptideMeter). 21:32
update from 21 months ago: retested the same supplier, result came back better, logged both
assay under label with good purity means you got less of the right thing. that is a fill problem, not a synthesis problem, your mileage will differ
99.4 against a certificate of 98.1 is fine. the same supplier landing low four times in a row is a question
has a supplier ever disputed a result posted here
nice result
whats the lot
sample handling on your end absolutely affects it. draw cleanly, ship fast, do not let it sit warm
unrelated but a single sample tells you about a single vial. that is genuinely all it tells you
which lab
one bad test does not condemn a supplier. one good test does not clear one. both halves get ignored equally
attach the pdf
posting my Medutest result on lot B-0329, what do people make of it
i told SSA about a result they would not have liked and they did not argue. credit where it is due
if you are testing to settle an argument you will not settle it with n of 1
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weigh it first
is quantity testing available as a separate thing or bundled
the honest limits: hobby chain of custody is weak and any result here should be read with that in mind
selection bias
anyone tested the same lot twice at different labs
when did you buy it
is anyone tracking results over time in a way they would share
what interests me is when the gap goes the same direction every time. once is noise, three times is a pattern
whats the underfill rate people are actually seeing
coming back after 10 months with a follow up result, where do i put it
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my sheet has 3 lots from CPC with a spread under a point, which is tight, n of 1 obviously
log the boring results too. a channel that only records failures produces a false picture, someone check my working
*that should say weekly
test it again
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 / 10mganyone had a result they think was a lab error rather than a bad vial
follow up a supplier disputing a result is rare here and it has never gone well for the supplier
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the widest spread in my data is about 2.6 percentage points across five lots from one supplier
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*PeptideMeter not the other one
underfill is more common than impurity. if you only test purity you are testing the less likely failure
my read after three years of this: purity is mostly fine across the market and fill consistency is where suppliers differ
*Medutest not the other one
ok so is it worth testing if the vial has already been through a warm transit
if the vial has been through a bad transit you are testing the transit as much as the supplier
what interests me is when the gap goes the same direction every time. once is noise, three times is a pattern
*VendorInvestigate not the other one
thats not great
Channel stats, last 30 days: 77 messages from 10 members.
post the lot, the purchase month, the lab, the number, and what you were expecting. that makes it useful later
New independent result logged — FGP, lot A-2418, purity 98.6% (PeptideMeter).
thats a fill problem
does anyone log the negative results, the boring ones
quantity testing is usually a separate line item and it is the one worth paying for
sorry to jump in weigh the vial before you reconstitute. it costs nothing and catches the common failure
the results in this channel skew because people test when they are suspicious. that is selection bias and it is real
weigh it first
how do you post a result so it is actually useful to somebody in a year
does a bad result on one lot condemn the whole supplier
i had a result i am fairly sure was a handling error on my side and i logged it as such
a result without a lot number and a purchase date is an anecdote with a pdf attached
certificate said 96.8 and the independent came back 99, is that a problem
follow up the results in this channel skew because people test when they are suspicious. that is selection bias and it is real
log the lot number
log the boring ones
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