Testing: the why, where and how of Covid tests

State health officials have said for months that accurate and accessible testing is a key tool in understanding and combating Covid-19 in Minnesota.

The most commonly administered Covid-19 tests in Minnesota are diagnostic tests, which determine whether you are infected with the coronavirus at the moment you're tested. Those are the tests that the state reports in its daily updates - and the tests that help epidemiologists understand the spread of Covid-19 across the state.

There are two types of diagnostic tests being used in Minnesota: PCR tests and antigen tests.

PCR tests are the ones you see most often in Minnesota. They're the nose-swab tests you'd get at your doctor's office, clinic or pop-up clinics; the saliva tests that you can get at sites across the state; or the saliva tests that residents of a handful of counties can order and administer at home.

PCR - which stands for polymerase chain reaction - tests are very accurate. They require specialized lab equipment to process the samples, so it takes some time - often a few days - to get your results.

Antigen tests, or "rapid tests," use either a nasal or throat swab to collect samples. They can deliver results pretty quickly - some are able to return results in 15 minutes.

The tradeoff is that antigen tests aren't quite as accurate as PCR tests, especially in people who aren't showing symptoms. While not as widely used as PCR tests, antigen tests have been available in Minnesota for some time. Here, they are most frequently used in long-term care facilities - where faster results might help a facility organize a response to a Covid-19 outbreak. Antigen tests weren't being reported in the health department's daily updates until recently.

The other types of tests, which are far less common, are called serology tests - and they help patients determine whether they've already been exposed to the coronavirus. (More on those below.)

When should I get tested?

In general, the Minnesota Department of Health recommends that people get a diagnostic test if they:

have COVID-19 symptoms; or

know that they were exposed to someone with COVID-19, even if they don't have symptoms.

But those recommendations come with some important caveats. Because testing supply stocks can fluctuate, some providers may prioritize testing for people who are older than 65, work in a school or health care setting, or who are first responders. You can check the health department's testing website to find out which criteria that sites near you are using to determine testing priority.

So unless you're going to one of the state's free pop-up events, it's best to contact your regular health care provider for information on availability.

How do I get tested?

There are several ways people can get Covid-19 tests in Minnesota.

Talk to your doctor or go to a clinic. If you have a regular doctor, call them to get a referral for a Covid-19 test. To avoid charges, make sure the testing location is in your insurance company's network. The state department of health maintains an active, updated list of testing sites across the state.

Attend a pop-up testing event. The state health department has been partnering with local communities to offer testing at pop-up sites across Minnesota. Testing at these sites is free and doesn't require patients to bring identification or have insurance. The health department does encourage people to schedule an appointment if they plan to be tested at one of its pop-up sites.

Go to a saliva testing site. The state has launched several sites across the state where residents can get saliva tests. The sites have regular hours and are open most days of the week. Testing is free and available to anyone who thinks they need a Covid-19 test. Patients don't need identification or insurance to be tested. Registration is not required but is encouraged. And remember to not drink, chew or smoke anything for at least a half-hour before you take the test.

Order an at-home saliva test: The Minnesota Department of Health recently launched an at-home saliva testing pilot program in two dozen counties or tribal nations around the state. People living in those counties can request a test through the mail. It will be shipped to their home and performed with the help of a health care professional over the internet. The sample will then be tested at a facility in Oakdale, and results will be available electronically in 24 to 48 hours.

The where of Covid testing

Carlton County testing sites include CMH Raiter Clinic, Min No Aya Win Human Services Center, MedExpress Urgent Care in Cloquet, Gateway Family Clinic in Moose Lake and Cromwell Medical Clinic.

There are a number of additional options in the Duluth-Superior area.

Testing at the Duluth Entertainment and Convention Center is available inside entrances across from the harbor noon to 7 p.m. Wednesday through Friday and 10 a.m. to 4 p.m. Saturday and Sunday. The saliva testing clinic at the DECC in Duluth is free, doesn't require a doctor's order and was seeing a quick turnaround for results recently, although lines can be long. While it is open to walk-ins, people are encouraged to register in advance to make an appointment at mncovidtestingappt.as.me/schedule.php.

On Monday the University of Wisconsin-Superior, in partnership with the U.S. Department of Health and Human Services and the UW System, opened a new rapid results testing site that can provide results in as little as 15 minutes. The temporary testing site is open from 2-6 p.m. Monday through Friday in the Mertz Mortorelli Gym in the Marcovich Wellness Center. Abbott BinaxNOW antigen tests that provide a result in about 15 minutes will be used, along with PCR confirmation tests for those who need them.

The testing site is open to Minnesota and Wisconsin residents 5 years of age or older, whether or not they are experiencing symptoms. Registration is required and can be done at doineedacovid19test.com. Participants will also retrieve results by logging into this portal after receiving an email that informs them that their results are ready. A limited number of spots are available daily on a first come first served basis. Masks are required.

Will it cost anything?

Covid-19 diagnostic testing should not cost you anything. Federal law requires tests and any associated office visit cost to be covered by insurance companies without what's called cost sharing. Minnesota's private health insurance companies have committed to these rules indefinitely.

If you get your insurance through Medicare or Medicaid, you shouldn't be charged, either.

To avoid charges, you need a doctor's referral for the test - and it needs to be in your insurance company's network.

If you're in a jurisdiction that's now offering at-home saliva tests and you want to sign up for one, you will be asked for insurance information, but the test will be free if insurance won't cover it - or if you don't have insurance.

And the state's pop-up testing sites bypass insurance altogether. The tests there are free and covered by the state.

When will I get results?

A PCR test result can take as little as a day or as many as several days to get back to the patient. The speed of return depends on several factors, including the availability of supplies, backlogs at labs and where a person is tested.

As mentioned above, antigen test results can be determined in a matter of minutes, the tradeoff being that they aren't as accurate as PCR tests.

If your results come back negative, the state recommends you continue your 14-day quarantine, because symptoms can pop up at any time. The incubation period of the virus is understood to last between two and 14 days.

Health department officials recommend being retested 12 days after you were exposed to the coronavirus.

What about antibody tests?

Serology tests, or antibody tests, detect Covid-19 antibodies - proteins the body produces to fight a virus, and a sign that someone has been exposed to the virus and recovered. Unlike diagnostic tests, these tests rely on blood samples. State and local officials have cautioned against a flood of these tests on the market that may not be reliable or accurate.

Antibody tests are a bit different from their diagnostic counterparts - and there isn't an equivalent statewide effort to offer antibody testing.

One reason for that is because it's not yet clear what the results of even the most reliable tests mean, for the average patient. It remains unclear if recovering from the coronavirus makes you immune to catching it again.

Timing is also tricky. It can take two to three weeks for your body to develop enough antibodies to show up in a test.

There are two clinical uses for antibody tests that can be beneficial right now: in children and in helping patients still fighting the disease.

In any case, talk to your doctor about whether you need a test and avoid purchasing one yourself, as they have been linked to scams, the Health Department says.