A study by IU and the Indiana State Department of Health used antibody testing to show about 186,000 people in Indiana may have been exposed to the coronavirus, which is 11 times more than what was known before. This makes the prevalence rate only 2.8%, which is generally low and could mean social distancing and hunkering down worked, scientist Nir Menachemi said.
Outside of research however, Menachemi sees no point in individuals getting tested for antibodies. While more tests for coronavirus antibodies are becoming available, what having the antibodies means remains unclear.
Dan Handel, chief medical officer for IU Health's south central region also does not recommend people get the test unless they know it is going to help in protecting themselves and others.
“The antibodies is still relatively unknown territory,” Handel said.
The antibody tests look for proteins in the blood that suggest the body has tried to protect itself from the virus it’s been exposed to, Menachemi said. There are two antibodies for COVID-19, IgG and IgM, Handel said, and only some people who have had COVID-19 develop these.
Generally speaking, having antibodies means immunity, but that has not yet been established for COVID-19, Menachemi said. That is a completely different set of studies that have yet to be conducted or published, he said.
While IU Health’s central lab in Indianapolis is looking at the possibility of using antibody tests, Handel said, they are not sure how they would incorporate these tests in their clinics at this time. He said they would be sure to vet the tests before administering them to patients, but as of May 14 no antibody tests are being implemented.
“The challenge with dealing with a virus that is so new is we don’t know clinically what the test results mean,” Handel said.
Both Handel and Menachemi said there is variability in reliability of the tests as well. Menachemi said at-home antibody tests available are not necessarily reliable and false positives or false negatives are possible.
Menachemi and Handel did not recommend any added precautions for someone who has taken a coronavirus antibody test and tested positive. They suggest taking the same precautions as anybody else.
“I think testing is ultimately designed to help guide decisions and behaviors, and if it doesn’t, I think it makes the need for the test for the individual less important,” Menachemi said.