Today, the EEOC added a new question and answer to its guidance What You Should Know About COVID-19 and the ADA, the Rehabilitation Act, and Other EEO Laws
addressing whether employers can require employees to get antibody testing before returning to the workplace. According the the EEOC, such a requirement would violate the Americans with Disabilities Act (ADA) because at this time antibody tests do not meet the ADA's "job related and consistent with business necessity" standard for medical examinations or inquiries. This is in contrast to tests for COVID-19, which the EEOC has said are currently permissible.
The EEOC also notes that the Centers for Disease Control has issued Interim Guidelines for COVID-19 Antibody Testing
. According to this guidance, antibody test results should not be used to make decisions about returning persons to the workplace.