The WCMR has released a video explaining the antibody serum test for the SARS-CoV-2 virus.
In it we discuss how antibodies confer immunity and how the role of disease prevalence changes how you interpret your test results. We also discuss why you can't just screen entire populations and think you will find all the people who are immune to SARS-CoV-2. The test that is discussed in the video is the Cellex qSARS-CoV-2 IgG/IgM Rapid Test, but the discussion is valid for any kind of diagnostic test. https://cellexcovid.com/