PCR (polymerase chain reaction) techniques are a much bigger thing than these particular covid-19 tests—and they are very useful and important. The trouble with these particular tests is they turn up the sensitivity way too high by repeating the process that doubles the sample size too many times—as if they were intentionally trying to get as many false positives as possible.
Even if they tested for the Covid virus, and even if they found a strand of genetic material UNIQUE to the COvid virus, and not shared with others, even if there were more than just basic building blocks that were once genetic material - it still would not prove that the patient is, or ever was SICK with a specific illness. What if the body fought it off?
The PCR is a laboratory assay meant to exagerate the presence of minute amounts of material that would otherwise be missed (needle in a haystack). According to the inventor, it doesn’t diagnose disease - how can it?