Afaik PCR remains terribly and wonderfully sensitive. Any positive that relies on a PCR cycle threshold can have false positives due to contamination and primer dimers, and false negatives due to bad prep. Ideally you’d need a positive in multiple wells, and retest any that were borderline or had a fraction of positive wells. But that’s probably not happening. Personally I’d be much more interested in getting an antibody test.
Apparently the other problem with false positives here is that there is lingering dead virus in some previously infected people whose RNA fragments can be detected by PCR. This is leading to some speculation about reinfection that some other researchers in Korea claim to have debunked.
Thank you, that was roughly my understanding. It was good to hear that the antibody tests seem to be quite accurate, with the alleged 99.9% accuracy rate per bfx's article you were already tagged in. We'll see.