(NEXSTAR) — As the omicron variant spreads and COVID-19 test appointments are hard to come by, many Americans are turning to at-home tests to determine if they’re infected. But if you test positive at home, do you need to report the case to the public health department or Centers for Disease Control and Prevention?

The short answer is it depends on where you live.

The CDC doesn’t instruct people to report the case as part of its self testing guidelines; however, many local health departments want that information. Some counties, like Marin County in California and Albany County in New York, have easy ways to report the positive test with an online form.

Other counties and local health jurisdictions, like San Francisco, instruct you to report the case to your primary health care provider. They are required to then report the case to the county.

Some places have no formal guidance on what to do. Massachusetts Department of Public Health told the Boston Globe it has no way to collect at-home test results.

The only way to tell what you’re supposed to do where you live is check with your local health department.

The fact that at-home test results aren’t being systematically reported to local health departments or the CDC means the COVID cases are being underreported right now.

“We have no idea what the true positivity rate is,” Atul Grover, executive director of the Association of American Medical Colleges, told PBS in December.

Even if you’re not required to report the case to any health authorities, it’s still a good idea to inform anyone you’ve been in close contact with over the past several days. They may need to self-quarantine or get a COVID-19 test.

If you test positive at home, you’ll also need to start following the CDC’s isolation procedures. Read more on what that entails here.