With the huge COVID-19 outbreak, many medical professionals have been developing and running tests concerning antibodies. They are researching into antibodies that have survived the Coronavirus and what makes them immune to the disease. Essentially, the test says if you have had the virus, and if you had recovered it very well likely means you are now immune.
However, there seems to be an issue with the antibody tests: limited availability and the reliability for the tests. If tests are incorrect, they could end up telling people they are immune to the virus, when in actuality they are not. Furthermore, it still isn't clear to medical officials that if you have previously had COVID-19, you are immune to the disease--it very well could be the opposite case.
The good news is officials are still working on more reliable tests that can be performed at home and/or can test for immunity. Much research still needs to be done in the field, but for now government officials are still emphasizing the need for individuals to take precautionary measures against the Coronavirus.
Information gathered from: https://www.cnn.com/2020/04/14/health/coronavirus-antibody-tests-scientists/index.html