UW Medicine: Rapid at-home tests not likely effective for asymptomatic people

By Adam Smith January 19, 2022 7:06 am

KGMIFILE - Boxes of BinaxNow home COVID-19 tests made by Abbott are shown for sale on Nov. 15, 2021, at a CVS store in Lakewood, Wash. The Biden administration's plan for health insurers to reimburse consumers for over-the-counter COVID-19 tests is recalling the model of a bygone era when the companies processed large volumes of claims from individuals _ with paper receipts. (AP Photo/Ted S. Warren, File)

SEATTLE, Wash. – University of Washington Medicine says it’s important to understand what these rapid at-home COVID tests can and cannot show.

Pathologist Dr. Geoff Baird says they’re great to have if you’re feeling ill.

“If someone is symptomatic, it makes the most sense to take the test that’s actually available at that time,” said Baird. “The clinical performance of an antigen rapid test is good enough such that you will get a pretty good result.”

But he says they’re not likely to be effective if you’re feeling well.

“Completely asymptomatic individuals testing themselves to see if it’s safe to go have a family reunion, or go to the theater, or go to an event, to go into close quarters,” said Baird. “They really do not have the diagnostic power to suggest that.”

He says that’s because a rapid test usually needs tens of thousands of viruses on a swab to come up positive.

But a PCR test can detect as few as 100 or 200 viruses on a swab.