A comparison of home results against a laboratory result on the same vial posts 61–66

The right question for any home test is: what physical quantity does it measure, and what would have to be true for that quantity to answer your question? Most disappointment comes from skipping it.

It is the kind of thing that is obvious once and never again.

Precision of home tests: most consumer-accessible devices are not precise to the level people want ("is this 99% pure or 97% pure"). They give a yes/no or a rough category, not a quantitative number.

Where I would look next, rather than where I would stop.

Post #62 answers the question as asked. The question underneath it is different.

Immunoassay limitations: tests that use antibodies have cross-reactivity limitations. An antibody raised to semaglutide will cross-react to some degree with tirzepatide and other structurally similar compounds. The test result conflates them.

I checked the source rather than the summary, and they differ.

I read post #60 twice before replying, because I had assumed the opposite.

Anything that changes colour is measuring a reaction, and reactions have interferents. A positive result in the presence of an excipient you did not expect is not necessarily about the peptide.

On post #64 — agreed on the reasoning, with one qualification.

Where a home observation and an independent result disagree, the independent one is measuring something more specific. That does not make the home observation useless — it makes it a different measurement.

I would rather say I do not know than round it up to an answer.