The EEOC just updated its Technical Assistance Q&A on COVID-19 and the ADA to distinguish between antibody tests (which detect past COVID-19 infections) and viral RNA tests (which detect active infections). The new guidance makes clear that antibody tests are not permitted under the ADA even though viral tests are permitted.
The EEOC justifies this distinction by pointing to CDC guidance from May 2020 that recommends against using antibody tests to decide whether employees can return to the workplace. The CDC guidance suggests that antibody tests should not be used for return-to-work decisions because there is insufficient evidence that antibodies provide protection against reinfection. And because CDC recommends against relying on antibody testing, the EEOC believes that antibody tests are not "job related and consistent with business necessity," a prerequisite for medical tests under ADA.
So while the accuracy and reliability of COVID-19 antibody tests has improved recently, because we still don't know the "durability and duration of immunity" in persons who have recovered from COVID-19, employers should not use antibody test results to make workplace decisions.
Antibody test results “should not be used to make decisions about returning persons to the workplace.”