CLEVELAND, OHIO (WJW) – Local health officials say coronavirus antibody testing can provide a better sense of how widespread and severe the virus truly is, but it remains unclear whether antibodies lead to immunity.
“The antibody test is a test looking for your body’s response to having had an infection,” said Dr. Pauline Terebuh, an epidemiologist on the Cuyahoga County Board of Health’s COVID-19 response team.
Terebuh said with diagnostic testing, like the kind done with nasal swabs, still limited, antibody blood tests can reveal who has had the coronavirus, even without displaying symptoms. The body creates antibodies while fighting the virus.
“Right now, at this point, the best way of using those tests is to get a sense for how many people may have been infected in the population in general or in certain groups,” she said.
Researchers statewide are conducting an antibody prevalence study of 1,200 people to provide a clearer picture of how many Ohioans have had the virus, how severe cases have been and the hospitalization and fatality rate.
“We’re only estimating, at this point, what portion are getting very sick and what portion are dying,” Terebuh said.
University Hospitals Chief of Clinical Pathology Dr. Christine Schmotzer said the hospital is testing for antibodies to resolve challenging cases among inpatients who have exhibited COVID-19 symptoms but tested negative.
She said because COVID-19 is a variable disease, it may not be detected in the nasal cavity where the diagnostic test sample is collected, and an antibody test can allow for proper treatment.
Schmotzer said multiple commercial vendors are now providing antibody testing that can be done at labs. She said accuracy has improved, with the U.S. Food and Drug Administration requiring specificity of at least 95 percent, meaning at least 95 percent of positive test results are accurate.
“The quality has been increasingly regulated, so the ones coming onto the market that laboratories and hospitals will be using are of higher quality than some of them that were available earlier on,” Schmotzer said.
However, she said much remains unknown about the effects of antibodies, and research remains underway to determine if antibodies lead to immunity to the virus.
“Right now, we do not know whether or not that antibody presence causes you to be immune to getting the coronavirus disease, either in the short term, next couple months, or in the long term,” Schmotzer said.
She said University Hospitals recommends testing only be done under doctor’s order through a qualified lab.
It should not be used to determine eligibility of returning to work or to satisfy curiosity among people who had coronavirus symptoms but were never tested, according to Schmotzer.
“We do not recommend using that as a return to work or a decision maker as to what type of work a person can do, because we don’t know if it confers that type of immunity yet,” she said.
She said to be wary of antibody tests marketed direct to consumer and done outside the supervision of a doctor and lab. Many of those tests have proven largely unreliable and have been pulled off the market amid increased FDA quality regulation.