How to Use POC tests with high false +ve results. Neat!!! From Michael Mina's tweet thread January 4th: "Many ppl instinctively worry that a false positive will mean an erroneous 10 day isolation and that huge numbers of people are going to require laboratory based PCR confirmation tests and this will overload the system. No, this is stuck-in-our-ways thinking...
With rapid tests, we don’t have to send in a PCR test for confirmation - it’s much simpler than that in a “rapid test world” - we can use a second rapid test... right there and have a confirmatory result in moments.
We do this all the time with HIV tests...
With HIV tests, if prevalence is low, ~50% of our positives may be false positive.
We don’t say the test is useless. We don’t make the person wait a week for a new test. We simply run the test on a second similar also imperfect test - combined they are very accurate.
W Rapid Ag tests, we can simply repeat the exact same test a second time. That will get rid of most false positives in five minutes. Alternatively we just use two different rapid antigen tests. Every house has 10 yellow tests and 2 red confirmatory rapid tests...
If you turn positive on yellow test, use the red one. They look same but have different molecules. Will not be expected to turn falsely positive for the same reason.
This can get false positives to <1:2000 or, one false positive every few years if testing 2x /week".