I wonder... are the current tests general for corona-viruses, or very specific to the COVID-19 SARS-COV2 variety?
A handful of manufacturers have produced antibody testing. Gen 1 antibody tests are tough because there are varied immune responses, interfereri g substances and well finding the specific antibody.
Without prper validation and vetting you get garbage in and garbage out.
Remember the hiv antibody testing? I do. It took quite some time to develop for accurate results.
So.. do you want results mow, or accurate results.