While the federal program to order free at-home COVID-19 tests ended last week, Mainers are eligible to order five free tests every month through a state partnership with Project Access COVID Tests.

Those tests may arrive after the printed expiration date.

But don’t be so quick to chuck those tests in the bin. Most likely, those tests are still good for several more months.

As early as January of this year and as recently as last week, the U.S. Food and Drug Administration has authorized extended expiration dates for 13 of the 22 at-home COVID tests approved for use.

Many of the most commonly found brands in local drug stores and provided by the federal and Project ACT programs, such as the BinaxNOW and the iHealth rapid antigen tests, have extended expiration dates that put their shelf life at six months past what’s printed on the box.

That’s because even after tests are manufactured, packaged and distributed, the test manufacturers conduct additional stability testing to determine if the tests have a longer shelf life than originally determined, according to the FDA.

As more information on the tests’ shelf life is gathered, the manufacturers can request that the FDA authorize an extended expiration date.

The FDA has twice authorized a three-month extension for iHealth’s rapid antigen tests. As of July, the FDA-approved extended expiration date is 12 months from the date of manufacture instead of six.

Project ACT, which is funded by the Rockefeller Foundation and provides free test kits to eight states, including Maine, will send five iHealth tests — recognizable by its bright orange packaging — to Mainers every month.

“Monthly reordering remains in place as we work to determine how long that option will continue as part of the broader program,” Maine Department of Health and Human Services spokesperson Jackie Farwell said in an email.

As of Aug. 1, Maine households have ordered 334,785 tests through the program since its launch in January, according to the Maine Department of Health and Human Resources.

To find the extended expiration date of an at-home COVID test, visit the FDA’s website at fda.gov/medical-devices/coronavirus-covid-19-and-medical-devices/home-otc-covid-19-diagnostic-tests.

To order free tests, visit accesscovidtests.org.