#test-results 2025-03-29

a point or two between the certificate and an independent result is inside what two labs disagree by

my read after three years of this: purity is mostly fine across the market and fill consistency is where suppliers differ, we shall see

underfill is more common than impurity. if you only test purity you are testing the less likely failure, i could be wrong

*PeptideMeter not the other one

a supplier disputing a result is rare here and it has never gone well for the supplier

while im here a single sample tells you about a single vial. that is genuinely all it tells you, thats one data point

weigh the vial before you reconstitute. it costs nothing and catches the common failure

is it worth testing if the vial has already been through a warm transit

do the results in this channel skew because people test when suspicious

weigh it first

98.1 against a certificate of 97.4 is fine. the same supplier landing low four times in a row is a question

i told KP about a result they would not have liked and they did not argue. credit where it is due

a result without a lot number and a purchase date is an anecdote with a pdf attached

how much does sample handling on my end affect the number

post the lot, the purchase month, the lab, the number, and what you were expecting. that makes it useful later

how many lots do you need before you can say anything about a supplier

is a purity-only test worth the money if underfill is the common failure

for the archive i have never regretted spending the money on a test. i have regretted not testing twice

i test roughly every tenth vial. it is a sampling strategy, not paranoia

whats the worst result anyone has logged and what happened next

the widest spread in my data is about 2.6 percentage points across five lots from one supplier

when did you buy it

one bad test does not condemn a supplier. one good test does not clear one. both halves get ignored equally

what interests me is when the gap goes the same direction every time. once is noise, three times is a pattern, ask me again in a month

nice result

selection bias

if you are testing to settle an argument you will not settle it with n of 1

sample handling on your end absolutely affects it. draw cleanly, ship fast, do not let it sit warm

the honest limits: hobby chain of custody is weak and any result here should be read with that in mind

Purity check: no report on file for lot G-0641. Nothing logged either way.

i had a result i am fairly sure was a handling error on my side and i logged it as such

thats a fill problem

log the boring ones

log the boring results too. a channel that only records failures produces a false picture

one data point

genuine question do you test every order or sample it

quick one assay under label with good purity means you got less of the right thing. that is a fill problem, not a synthesis problem

posting my Medutest result on lot A-2418, what do people make of it

log the lot number

for the archive update from 20 months ago: retested the same supplier, result came back better, logged both

quick one is quantity testing available as a separate thing or bundled

thats within range

my vial assayed under label but the purity was fine, which matters more