It’s important to note up front that the accuracy of the many different antibody tests on the market varies a lot

Remember Theranos? Theranos got to a billion dollar valuation because FDA regulation of diagnostic tests was so poorly enforced. In the interests of speed, they’re doing even less than that for Covid serology tests — which strikes me as a bit odd given their refusal to let qualified-but-not-FDA-certified research labs process naso-pharyngeal or sputum tests. For the whole Theranos story read John Carreyrou’s Bad Blood. Great read, BTW.