It looks like the covid-19 antibody tests that are marginally available in some places are not reliable enough to be useful. An added problem is no one yet knows what a positive test means for immunity. There is a suggestion that the test may be particularly unreliable for those under 40.
https://www.theguardian.com/world/2020/apr/17/roche-coronavirus-antibody-test-uk
https://www.bbc.com/news/uk-52335210
https://www.telegraph.co.uk/news/2020/04/18/coronavirus-antibody-test-kit-covid-19-prick/
https://www.theguardian.com/world/2020/apr/17/roche-coronavirus-antibody-test-uk
https://www.bbc.com/news/uk-52335210
https://www.telegraph.co.uk/news/2020/04/18/coronavirus-antibody-test-kit-covid-19-prick/
