Experts praised the news as a welcome endorsement of the importance of rapid and widely available testing while the nation continues to struggle in its fight to rein in the coronavirus, which has so far killed more than 204,000 people in the United States.

But the test numbers cited by federal officials, experts said, are nowhere what is needed to contain the spread of the virus.

“I’m happy that they are trying to invest in technologies that would expand the number of tests that could be done in the U.S.,” said Jennifer Nuzzo, an epidemiologist at the Johns Hopkins Bloomberg School of Public Health. “That said, 150 million tests is really a very small drop in the bucket, considering how these tests are envisioned to be used.”