This is a continuation of a long topic, addressed by post number rather than by page. Start at post 1 · go to the accepted answer.
The record shows what was measured. Everything beyond that is inference and this site tries to keep the line visible.
Trying to state the purity-only position in a way that someone who disagrees would recognise as fair, because I do not think the version in this thread passes that test.
Confirming post #62 from a second method, which matters more than confirming it from a second person.
A record with four results over sixteen months is a thin record rather than a bad one, and the honest description says which.
If it helps: the failure mode here is usually boring rather than dramatic.
Repeat testing: if you want to verify the same lot a second time, testing with a different service strengthens the conclusion. Testing with the same service verifies reproducibility but uses the same method.
Careful with the language on purity-only. "Not detected" and "not present" are different findings and the first is a statement about the method.
On purity-only the community has more anecdote than the confidence in this thread implies, and I include my own contribution in that.
Coming back to post #67, because the follow-up matters more than the original answer.
It does not extend to lots nobody has seen, it is not a recommendation, and it says nothing about anything other than what was measured.
If anyone can point at the primary source I would be grateful.
Something worth flagging about purity-only: the strongest-sounding claims in this thread are the ones with no source attached, which is the usual pattern and not a coincidence.
That matches what I have seen, for whatever a single anecdote is worth.
Confirming post #74 from a second method, which matters more than confirming it from a second person.
The bit of purity-only that nobody enjoys is that the answer changes depending on what you are trying to decide with it. Say what the decision is and the thread will converge.
Repeat testing: if you want to verify the same lot a second time, testing with a different service strengthens the conclusion. Testing with the same service verifies reproducibility but uses the same method.
That is the shape of it. The detail is where I would expect to be corrected.
If you are new and reading this thread for the answer to purity-only: the answer is conditional, the conditions are in the third reply, and the rest of the thread is worth skipping.
The arithmetic in post #80 is right; the assumption feeding it is the part to check.
The record shows what was measured. Everything beyond that is inference and this site tries to keep the line visible.
The disagreement above is smaller than it looks once the terms are fixed.
I have three months of notes on purity-only and the honest summary is that the trend is real and the week-to-week numbers are noise. I nearly drew the opposite conclusion from the first fortnight.
A record with four results over sixteen months is a thin record rather than a bad one, and the honest description says which.
Caveat: everything above assumes the paperwork is what it says it is.
No notes. Posting so the count is not one.
Repeat determination on the same product line months apart is the measurement that speaks to consistency, and consistency is what most buyers actually want.
The record shows what was measured. Everything beyond that is inference and this site tries to keep the line visible.
Nothing above should be read as advice about what anyone else should do.
It does not extend to lots nobody has seen, it is not a recommendation, and it says nothing about anything other than what was measured.