The longest-used assay depends on ingredients from wild animals, but regulators are now approving the use of animal-free alternatives. Here’s how these tests work. A pyrogen is any molecule that ...

The free COVID-19 tests the federal government recently rolled out will expire soon, but there is an explanation for that. Two weeks ago, the U.S. Department of Health and Human Services ...

While none of the free COVID-19 tests being shipped by the U.S. Postal Service this year will have already expired, officials acknowledge many now arriving in mailboxes will likely see their shelf ...

The federal government is once again offering free COVID-19 tests to families nationwide. Families can order up to four free ...

The federal government is once again offering free COVID-19 tests to families nationwide. Families can order up to four free COVID-19 tests through the U.S. Department of Health and Human Services ...