FDA Warns Providers About Limits of SARS-CoV-2 Antibody Tests

The FDA late last week issued a letter warning healthcare providers about the limits of serological tests to detect SARS-CoV-2 antibodies. The agency is urging clinicians to “not use serological (antibody) tests as the sole basis to diagnose COVID-19 but instead as information about whether a person may have been exposed.”

The agency said it “is not aware of an antibody test that has been validated for diagnosis of SARS-CoV-2 infection.” The tests measure IgM or IgG antibodies, but IgM antibodies may not develop at all, and IgG antibodies usually don’t develop until later in the disease process. Therefore, using such tests to diagnose COVID-19 will miss infections.

FDA letter to healthcare providers