Antibody testing may expand in Washington state — but not to send people back to work

Gov. Jay Inslee on Tuesday said state officials are reviewing the possibility of using antibody testing, to retroactively measure the spread of the novel coronavirus.

However, he said the testing wouldn't be used as a means of clearing those who test positive to return to work.

Inslee said state officials had been in talks with the manufacturer Abbott Laboratories, Inc, "about the potential of expanding large-scale surveillance antibody testing in the state."

Abbott's Covid-19 antibody test, which is conducted via a blood draw, is already in use by the University of Washington's Virology Lab. The test detects novel coronavirus antibodies, the proteins created by the immune system in response to the presence of a virus, rather than the virus itself.

Virology Lab officials have reported the test has a perfect rate of detecting antibodies in those who indeed have them. However, they've cited a 99.6% rate of specificity, meaning there's some potential to see false positives for those who haven't actually produced novel coronavirus antibodies.

The Abbott test must be ordered at the discretion of a health care provider —many of whom have been reluctant — per the Virology Lab's current protocols. It wasn't immediately clear on Tuesday what testing referrals would entail if Abbott's test was adopted at the state level.

Yes, Covid-19 antibody tests are really available in Seattle. But patients have been told otherwise

"So we think this can have potential utility as a surveillance tool to let us know what the presence of the disease really is," Inslee said. "It's also very important to guard against a second wave, because sometimes you can have asymptomatic people for quite some time before you even recognize it's present."

Inslee added that the tests wouldn't be used to issue social clearance to people who test positive, citing conventional scientific wisdom that the protective qualities of Covid-19 antibodies remain undetermined.

"We are talking to some outfits that might be able to help," he said. "But we have to realize it's for surveillance purposes — not for a passport to be able to go back to work."