COVID testing FAQ: How accurate are at-home tests? Where can you find one in Minnesota?

As the COVID-19 pandemic continues to affect daily life in Minnesota and cases rise due to the fast-spreading omicron variant, options for testing have expanded.

But with an abundance of choices come questions about which tests to choose and where to find them.

Here are some of the most commonly asked questions.

What is the difference between a PCR and an antigen test?

PCR tests are the most accurate for determining if you have COVID-19, according to the Minnesota Department of Health (MDH). These tests are administered with a nasal swab, an oral swab or by taking a saliva sample. You can take a PCR test whether you're symptomatic or not.

Antigen tests, also called rapid tests, produce results more quickly. These tests are given with a nasal swab and may not be as accurate, especially for people who are not showing symptoms. However, a positive test is considered a probable case of COVID, according to MDH. A public health worker will follow up to give someone who tests positive recommendations on how long to isolate. If you take a rapid test at home, you will not receive those recommendations as home tests are not reported to MDH.

Do at-home COVID-19 tests detect the omicron variant?

Yes, but U.S. health officials say early data suggests they may be less sensitive at picking it up.

A new real world study showed that the Abbott BinaxNOW rapid test can detect the variant in most people who are infected with high levels of Omicron. The antigen tests detected 65% of infections overall and 95% of infections in people with high viral loads. The study, which took place at a community testing site in San Francisco earlier this month has not yet been reviewed by experts.

Government recommendations for using at-home tests haven't changed. People should continue to use them when a quick result is important.

"The bottom line is the tests still detect COVID-19 whether it is delta or alpha or omicron," says Dr. Emily Volk, president of the College of American Pathologists.

Government scientists have been checking to make sure the rapid tests still work as each new variant comes along. The Food and Drug Administration said preliminary research indicates they detect omicron, but may have reduced sensitivity. The agency noted it's still studying how the tests perform with the variant, which was first detected in late November.

Where can I find rapid at-home tests in Minnesota?

At-home rapid antigen tests can be found at pharmacies, grocery stores, health care providers and online. Post-holiday, tests may be difficult to find. Setting stock notification alerts could help. These websites, popular for years with gamers and shoe fanatics, are now being used for testing. NowInStock and other sites scour the internet for stock and update when they find it. You can set alerts that go to your phone, e-mail or browser.

How can I get a free test mailed to me?

The state is offering free at-home PCR tests through Vault Medical Services. You can request a test whether you have symptoms or not. Orders are delivered via DoorDash. Tests will not be shipped or delivered on Sundays or holidays. Tests are self-administered with supervision on Zoom. Right now, results are delayed due to high testing volume. Order a test here.

There is no limit to the number of Vault tests you can order, but you cannot order a new one until you receive results from an outstanding test.

What about state-run testing sites? Where are they, and how do you get a test at one?

The state's COVID-19 Community Testing Sites are free and do not require proof of insurance. Walk-in tests are welcome, but the state strongly encourages making an appointment at the location you will visit. Without an appointment, you will have to wait in line. Results are available in 24-72 hours for PCR and in 15 minutes to 3 hours for antigen tests.

Minneapolis Convention Center

Monday-Friday: 9 a.m.-7 p.m.

Saturday: 10 a.m.-6 p.m.

Enter the building on the northwest side off 2nd Avenue, nearest to the west skyway. Free parking is available at the Plaza Parking Ramp. Be sure to request a parking voucher on-site in the testing room.

MSP Terminal 1, Level 2 Blue Ramp

Daily: 7 a.m.-7 p.m.

Staff will validate parking for those who are testing.

St. Paul Roy Wilkins Auditorium Exhibit Hall

Sunday: 11 a.m.-4 p.m.

Monday-Thursday: 11 a.m.-6 p.m.

Friday-Saturday: closed

Limited free parking is available at the RiverCentre Parking Ramp. Metered parking near Rice Park is also available.

Other testing locations: https://mn.gov/covid19/get-tested/testing-locations/community-testing.jsp

What if I'm told to pay for a free test?

MDH advises that you will not have to pay for free tests. If you have insurance you will be asked to provide that information so that your insurance can pay for the test. If your insurance does not cover COVID tests, the state will pick up the bill. If you don't have insurance, you can still take a free test.

If the Vault website asks for your credit card information, do not provide it. Close out of the browser and try to order your test again from a new or incognito browser. If you have been charged for a test, send an e-mail to testathome.mdh@state.mn.us.

Are there other places that do on-site testing?

Tests are also available at community clinics. Search a list of clinics using your ZIP code here.

Some doctors offices also offer drive-up tests.

How long after testing positive do you have to keep testing to make sure you're in the clear?

There's not a requirement or broad recommendation that everyone take a test before they stop isolating, but the Centers for Disease Control and Prevention (CDC) has laid out some guidance for those who may want to, according to an MDH spokesperson. If a patient meets criteria to end isolation after five full days, they may do so. If that individual has access to a test and wishes to take a test, an antigen test is the best approach.

If a patient meets criteria to end isolation after 10 days, they do not need to test. Those who are immunocompromised or severely ill should consult their physician regarding testing. Their recommendation may vary depending on the patient and situation, according to the CDC.

How do I know if a test purchased from a store or online is legit?

Here is a list of COVID tests that the FDA has authorized for emergency use. Brands include Binax, Inteliswab and On/Go.

Costs for a pack of two antigen tests could run from $14 at the low end to $35 online. The Wall Street Journal reported last week that Walmart and Kroger were raising prices on Binax tests.

Do I have to report a positive result from an at-home test to MDH?

If you are self-testing and are not connected to a setting with specific testing guidance, you do not need to report the results of the self test to local or state public health agencies. However, if your test comes back positive, you have COVID-19 and should follow isolation guidelines.

Are tests that sat outside in the cold OK to use?

Vault test kits are stable from 35-86 degrees Fahrenheit (2-30 degrees Celsius) but will be fine if they are colder than that for a short period of time. It is recommended to warm tests to room temperature before using, according to MDH.

Meanwhile, Minnesotans are receiving free COVID-19 at-home test kits offered by the federal government.

Although each one is slightly different, most contain a liquid known as a reagent that can freeze in cold temperatures.

The Food and Drug Administration said the at-home tests can still be used if they have been out in cold weather.

"In order to ensure appropriate test performance with a test that is delivered to you in below-freezing temperatures, you should bring the package inside your home and leave it unopened at room temperature for at least two hours before opening it," the agency said in a statement.

However, the agency did not explicitly say tests would still be good if, say, left in a curbside mailbox in 10-below weather for six to eight hours.

Looking to get vaccinated? Find your vaccine here.

What questions do you have about COVID tests in Minnesota? Submit your question here and we'll try to find the answer.

The Associated Press contributed to this report.