Test blitz comes with concerns

Results tracking difficulties spur questions of data reliability

WASHINGTON — After struggling to ramp up coronavirus testing, the U.S. can now screen several million people daily thanks to a growing supply of rapid tests. But the boom comes with a new challenge: keeping track of the results.

All U.S. testing sites are legally required to report their results, positive and negative, to public health agencies. But state health officials say many rapid tests are going unreported, which means that some new COVID-19 infections may not be counted.

And the situation could get worse, experts say. The federal government is shipping more than 100 million of the newest rapid tests to states for use in public schools, assisted living centers and other new testing sites.

“Schools certainly don’t have the capacity to report these tests,” said Dr. Jeffrey Engel of the Council of State and Territorial Epidemiologists. “If it’s done at all, it’s likely going to be paper-based, very slow and incomplete.”

Early in the outbreak, nearly all U.S. testing relied on genetic tests that could be developed only at high-tech laboratories. Even under the best circumstances, people had to wait about two to three days to get results.

Experts pushed for more “pointof-care” rapid testing that could be done in doctors offices, clinics and other sites to quickly find people who are infected, get them into quarantine and stop the spread.

Beginning in the summer, cheaper, 15-minute tests, which detect viral proteins called antigens on a nasal swab, became available. The first versions still needed to be processed using portable readers.

The millions of new tests from Abbott Laboratories now going out to states are even easier to use. They’re about the size of a credit card and can be developed with a few drops of chemical solution.

Federal health officials say about half of the nation’s daily testing capacity now consists of rapid tests.

Large hospitals and laboratories electronically feed their results to state health departments, but there is no standardized way to report the rapid tests, which are often done elsewhere. And state officials have often been unable to track where these tests are being shipped and whether results are being reported.

Besides tallying new cases, COVID-19 testing numbers are used to calculate a key metric on the outbreak: the percentage of tests positive for COVID-19. The World Health Organization recommends that countries test enough people to drive their percentage of positives below 5 percent.

And the U.S. has mostly been hovering around or below that rate since mid-september. The figure is down from a peak of 22 percent in April.

But some disease-tracking specialists are skeptical. Engel said his group’s members think they aren’t getting all the results.

“So it may be a false conclusion,” he said.