In the last week, COVID-19 antibody test kits began surging into the commercial market. The test looks for antibodies present in the blood when the body is responding to a specific infection, like COVID-19. It detects the body’s immune response to the infection caused by the virus rather than detecting the virus itself.
Commercially available test kits, such as those that can be ordered online and performed at home, have not been approved or validated by the U.S. Food and Drug Administration (FDA). Initial evaluation of the tests show specificity lower than 50%, with the highest at about 80%. Specificity is the ability to correctly detect the COVID-19 antibody.
This means that home test kits have a high rate of both false positives and false negatives. FCN’s Chief Medical Officer, Jim Hopper MD, recommends waiting for an FDA-approved test. “Any available antibody test kit that can be used at home is – at best – as likely to misidentify prior infection as it is to correctly identify it.”
Dr. Hopper’s evaluation of commercially available test kits is in alignment with the FDA, which posted this statement on their website:
“The FDA is not aware of an antibody test that has been validated for diagnosis of SARS-CoV-2 infection. While the FDA remains open to receiving submissions for these tests for such uses, based on the underlying scientific principles of antibody tests, the FDA does not expect that an antibody test can be shown to definitively diagnose or exclude SARS-CoV-2 infection.”
It is still unknown what a positive antibody test means for COVID-19. For some viruses, a person with a positive antibody test would be considered “immune” to re-infection, however we do not know if this is the case with COVID-19. Antibody testing provides valuable data for medical research and our understanding of the virus, however it should not be used to change our approach to the pandemic.
Regardless of an antibody test result, it is imperative to continue our efforts to reduce potential exposure and spread. Follow stay-at-home orders, limit time outside the home to essential activities, and follow safety protocols for handwashing, wearing a protective face mask at work or in public, avoiding touching the face, and disinfecting high-touch surfaces.