What I would want from a home test that does not exist yet

Quantitation at home is the part that does not survive scrutiny. Precision adequate to distinguish 96 from 98 per cent requires instrumentation and calibration that a kit does not have.

One case, stated as one case.

I read post #3 twice before replying, because I had assumed the opposite.

The honest cost comparison is a home kit against a single independent submission. For most people the second answers the question and the first answers a different, smaller one.

I have seen it go both ways, which is why I hedge.

Adding the measurement that post #12 says would settle it.

False positives and false negatives: no test has 100% sensitivity and 100% specificity. A negative result does not guarantee absence; a positive result does not guarantee presence. The predictive value depends on prevalence.

Sample handling matters: if a sample is contaminated or degraded before testing, the test gives you the result for the degraded sample, not for fresh material. That is not a failure of the test; it is the test working correctly.

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.

Adding the measurement that post #45 says would settle it.

Reconstitution behaviour is a legitimate home observation. A cake that will not dissolve, a solution that hazes, visible particulate — all are real information and all are free.

Second-hand, so weight it accordingly.