Biden administration officials told The Associated Press that Americans have placed 68 million orders for packages of tests, which contain four COVID-19 tests each. That leaves about 46 percent of the stock still available.

"We totally intend to sustain this market," Dr. Tom Inglesby, testing adviser to the White House COVID-19 response team, told AP about the unclaimed tests. "We know the market is volatile and will come up and down with surges in variants."

The shortfall in tests being claimed is likely because of a significant drop in COVID-19 cases across the United States, as well as an easing of restrictions such as vaccine or masking mandates in primarily Democrat-led states in recent weeks.

"There is no question some people found out they were positive from taking one of these tests and were able to keep other people from getting infected," Tim Manning, supply coordinator for the COVID-19 response team, told AP.

On the first day that COVID-19 tests were made available in January, the COVIDtests.gov website received more than 45 million orders, officials told AP. Fewer than 100,000 orders per day are coming in now.

About one month ago, the federal government said it would procure another 100 million COVID-19 tests via iHealth Labs.

"This effort supports the president's plan to deliver 500 million free at-home COVID-19 tests to the nation in response to the Omicron variant," the Department of Defense said in a Jan. 29 statement. "The procurement was funded through the American Rescue Plan Act to supply critical medical resources to the nation."

Biden had announced the new testing measure after facing criticism that his administration has mainly focused on getting people vaccinated and that they haven't done enough to encourage testing amid the spread of the Omicron coronavirus variant.