Testing people to see if they have COVID-19 is a high priority, but a different kind of test may reveal who might already be immune to the disease, even if only temporarily.
The testing, known as serology, tracks down antibodies, which provide a window into a patient’s infection history.
The ability to detect antibodies can reveal whether someone has had COVID-19 before, even if they were not diagnosed or they never felt sick.
According to the Food and Drug Administration, “Serological tests measure the amount of antibodies or proteins present in the blood when the body is responding to a specific infection, like COVID-19. In other words, the test detects the body’s immune response to the infection caused by the virus rather than detecting the virus itself."
Dr. Gregory Poland, with the Vaccine Research Group at Mayo Clinic, said an antibody, or serologic, test may reveal whether health care workers have developed immunity.
“It would be very useful, helpful, even reassuring to people to know, ‘Have I been infected, and I am potentially protected now?’ Imagine in the workplace,” Poland said. “It would be a great help to know if I had indeed been infected and now recovered from that and now able to take care of patients.”
According to Mayo Clinic, while the blood test is not used for initial diagnosis, on a large scale, serology can provide essential information in tracking where the disease has been and forecasting future hot spots.
Gov. Ron DeSantis said during his news conference Saturday that Florida Department of Health has ordered serology tests that can detect coronavirus antibodies in people who aren’t currently sick.
“We think having the serology test, having access to that, will be really important because there may be people who had an illness in February or March and didn’t go to the doctor for it, and maybe they think, ‘Maybe I had it,’" DeSantis said. "And then you can also spot-check a representative sample to see how many people in our society have the antibodies.”
The governor didn’t give a timeline for when COVID-19 antibody testing would be available.
Poland said it’s not yet known whether the presence of antibodies specific to COVID-19 means a person will never be reinfected.
Mayo Clinic said what is clear is that serology will contribute to wide-ranging areas of COVID-19 diagnosis, treatment and research.