Ok, so after hearing a poster here comment recently on how her DC's pediatrician told her "you can test positive on an antigen test for long time after you're no longer contagious" I've now heard this from two other unrelated people -- both of whom claimed it was "based on official articles they read" claiming sources like the CDC, and in conjunction with discussion/confirmation from (family member/friend) doctors.
I have always heard that it's possible to test positive on a PCR test for loooong after you are no longer contagious, but that rapid/antigen tests are a fairly good indicator that you are *currently* positive and likely infectious. I just spent way too much time trying to find some credible source that comments on false-positive rates in antigen tests, and/or has any evidence-based proof of whether a positive antigen tests means someone is likely contagious. I can not find a thing. I found a few random news articles with a quote from some "expert" -- but they quotes don't even all agree, and none point to any formal guidance, studies, or evidence.
Does something exist? Does anyone know where these people are coming up with this "you'll test positive on a home test for a long time" thing? At first I just thought someone was mixing up the difference between PCR and antigen tests, but it's so odd to me I'm hearing this from multiple unrelated places all of a sudden.