Roche gets FDA approval for Covid-19 antibody test with 99.8% specificity (cbsnews.com)

That's pretty great. It'd be interesting to run a study with the test in NY and compare it with the 21% positive rate the state found with their test. If we're expecting that high a percentage to be positive, a 1/500 false positive rate should be more than enough to validate that number and get good data in hotspots like NY.