Antibody (Serology) Tests for COVID-19: a Case Study

Serology (antibody) tests to detect previous SARS-CoV-2 infection have been in high demand from the beginning of the COVID-19 pandemic. The initial shortage of diagnostic tests coupled with asymptomatic infections led to a significant demand for serology tests to identify past infections. Despite serious limitations on the interpretation of a positive antibody test in terms of immunity to SARS-CoV-2, antibody testing was initially considered for release from social distancing, return to employment, and “immunity passports.” The regulatory approach to antibody tests was limited; manufacturers were encouraged to develop and market antibody tests without submitting validation data to the FDA. FDA guidance grew more stringent, but many poor-quality tests were already on the market—potentially inappropriately used for individual decision-making. This is a case study describing COVID-19 serology tests and the U.S. market and describes lessons learned for a future health security crisis.