Public health experts say many more tests will be needed to cover everyone who will be identified by this project. And waiting up to five days for the test's results, as some people still do, is a problem.
"The delay in how long it takes to get the results remains too long to make contact tracing very effective," says Dr. Sandro Galea, dean of the School of Public Health at Boston University.
But Galea notes that testing capability could change any time.
"Yesterday, we probably did not have the tools," he says. "Whether we'll have the tools tomorrow remains to be seen."