Mayo Clinic doctors find many COVID-19 antibody tests fail their quality standards: ABC News exclusiveMay 21, 2020
In partnership with the ABC News Investigative Unit, Mayo Clinic doctors in Arizona and Minnesota ran over 4,500 tests on both rapid and slower, traditional lab antibody tests. Nineteen different COVID-19 antibody brands selected by the clinic were tested in under a month, a process that would normally take around a year, they said. For the review, the clinic did not provide brand names to ABC News.
“We evaluate tests and make sure they perform well before we offer them to our clinical colleagues and to providers to use,” said Dr. Elitza Theel, an associate professor of laboratory medicine and pathology at Mayo Clinic and the researcher who put the laboratory test kits to a test themselves. “And so this really underscores why laboratories continue to evaluate and validate tests thoroughly before offering them for clinical care.”
Of the 19, nine were rapid antibody tests designed to give a result in just minutes. But four out of nine of those rapid antibody tests examined failed the Mayo Clinic’s testing process for various reasons, including low accuracy and physical problems with the actual tests. Quality issues like these, the team said, are why the Mayo Clinic has not yet made a decision about using finger-prick blood tests to look for antibodies in its own clinical patients.
“Our job is every day to make sure that we’re giving the right answer on every specimen from every patient,” Grys said.
The Mayo Clinic team also saw performance issues with more sophisticated laboratory blood analysis’ in which a larger sample of the patient’s blood is drawn and taken away to be tested in a lab. They found these laboratory tests fared slightly better but still had problems.
“Out of the 10 test kits that we looked at, there were four that really had A plus ratings, there were a couple that were in the B ranges, and there were two or three that were in the F range that we definitely wouldn’t want to use in a clinical laboratory,” said Theel.
Theel said four of the kits tested had been given emergency use authorization by the Food and Drug Administration – each of which received A plus ratings in the Mayo Clinic review. The other tests are either under evaluation or had not applied for the authorization.
Theel’s team found that one laboratory test came back with a false positive rate of 17% — meaning that 17 out of 100 people tested, who were never infected, would be falsely told they had antibodies.
“If a kit has a false positive, the concern is we think they have antibodies against the coronavirus, but really they don’t,” Grys said. “So then that person might be at risk because they think they don’t maybe need to wear a mask, or they can care for someone who’s sick with the coronavirus, and they would be exposed and not protected.”
Experts say a key metric for testing is something epidemiologists called “specificity” — meaning how well a test identifies who does not have the novel coronavirus. While Theel said that no…