For example, the accuracy quoted for pregnancy tests is meaningful, as there is a pretty obvious gold standard for determining if a woman is actually pregnant. With "COVID-19" or "SARS-CoV-2", no such thing exists. All quoted sensitivities and specificities for their PCR and antibody tests are bogus, logical frauds, as determining these depends upon having samples of *known * infected and non-infected, but there is no way of knowing. Estimating using another test of some less-than 100% accuracy presupposes knowing that accuracy and, worse, applying that test to groups to obtain samples with some probability of being infected requires knowing the infection rate.