Dr. Scott Gottlieb on Monday warned about the accuracy of antibody tests for the coronavirus, telling CNBC that people should not trust the results of only one test.
“If you do go out and get an antibody test, and you get a positive result, meaning you have the antibodies, I would suggest you repeat it,” the former head of the Food and Drug Administration said on “Squawk Box.”
Gottlieb said the tests have a high false positive rate, making it difficult to know whether a single result is credible. He said the likely accuracy of the test increases if the same person gets two positive determinations in a row.
“Quite frankly, if it was me, I would repeat it three times,” said Gottlieb, a CNBC contributor who sits on the boards of Pfizer and biotech company Illumina. “I know they’re expensive, but I wouldn’t put confidence in any one test.”
However, a person who is certain they have antibodies for Covid-19 could be “reasonably confident” that they have some immunity to the virus, he said. This applies to people who were sick and diagnosed with Covid-19 and then recovered, he said, as well as individuals who never developed symptoms and learned of the presence of antibodies through a test.
Gottlieb reiterated that there is uncertainty about how long, or how strong, that immunity is. “It’s probably going to be months. It might be a year or more,” he said Monday.
“But I think for the next six months, you could be reasonably confident that you’re not going to get reinfected and if you do, you’re going to have a mild case,” he added. “I wouldn’t go out and do crazy things, but I’d feel more confident going around, if it was me.”
There are more than 1.1 million confirmed cases of Covid-19 in the U.S., according to Johns Hopkins University data on Monday morning. At least 67,686 people have died.
Gottlieb is not the only person warning about the accuracy of antibody tests, many of which were able to get on the market without approval from the FDA, according to The Washington Post.
Roche CEO Severin Schwan last month called some antibody tests “a disaster.” The Swiss pharmaceutical giant announced Sunday that its antibody test received emergency use authorization from the FDA.
“It’s highly reliable, it’s a very precise test, and indeed that has been an issue with the first generation of tests,” Schwan told CNBC’s “Squawk Box Europe” on Monday. “So now, patients and societies can rely on a highly, highly precise test.”
Schwan said he believes it is “very likely” people who have recovered from Covid-19 develop some immunity.
“We need studies to really see whether those people who have been infected once are subject to reinfection. But there’s a high likelihood” that they will develop some immunity, he said.
— CNBC’s Chloe Taylor contributed to this report.