(NEXSTAR) – You’ve done it. You were finally able to track down some at-home COVID-19 testing kits. But once you have them, how long can they last before they’ve expired?

Earlier this month, as many as 1 million COVID test kits expired in a state-run warehouse in Florida. The Food and Drug Administration recently determined that, despite expiration dates on the test kits, the tests are still salvageable and will be rolled out into communities.

This contradicts the current guidance from the Centers for Disease Control and Prevention, which states tests and test components should be thrown away after their expiration date.

So how long is that COVID test really good for?

Ultimately, it comes down to which type of test you have.

The BinaxNOW COVID-19 Ag Card test, for example, recently received FDA approval for an extended shelf-life after testing showed the kits were good for up to 15 months. Each brand marks its at-home test kits with their own expiration dates on the packaging.

According to Dr. David Dowdy, an associate professor of epidemiology at the Johns Hopkins Bloomberg School of Public Health, it’s usually the components on the testing strip that expires.

But what if your kit expires before you use it?

Both Dowdy and OhioHealth Infectious Disease Expert Dr. Joseph Gastaldo recommend avoiding expired tests because the results can be skewed.

“But generally speaking, if you get a positive result, it’s likely to be positive, even if the kit is expired,” Dowdy explains. “Negative results can’t be taken as definitively negative, though.”

“If there is a negative test, if somebody has symptoms or there’s a negative test in somebody who’s asymptomatic, with an expired expiration date, that test would seem to be less reliable,” Gastaldo said.

If you are unsure about your test results, experts recommend seeking out another test or speaking with your health care provider.