At-home COVID-19 tests: Ways to determine if you need to retest

During the COVID-19 pandemic, ensuring health and safety is a top priority for the world. While Omicron surged in February 2022, the federal government made hundreds of millions of antigen COVID-19 tests available to U.S. residents for free.

How to order free at-home COVID-19 tests

You can order free, at-home antigen COVID-19 tests at www.COVIDTests.gov. You are provided four free at-home tests per residential address. At-home tests also can be ordered at no cost for Wisconsin residents by visiting this Wisconsin DHS site. A limited number of collection kits are available each day in Wisconsin.

Differences between PCR and antigen tests

Polymerase chain reaction (PCR) tests successfully detect even the smallest amount of coronavirus genetic material in a sample. According to Wisconsin Department of Health Services, antigen tests are not as accurate as PCR tests.

Antigen tests (like the at-home tests) don’t amplify the virus they are looking for, meaning there has to be a good sample of material or presence of virus in the system. For this reason, you may miss early COVID-19 cases with antigen tests and accuracy isn’t as dependable as PCR tests.

However, people can use at-home tests with symptoms or exposure. Note: You may need to verify with your local school or workplace if at-home COVID-19 tests are acceptable.

“Results of this test are often fast, anywhere from 15 minutes to one hour,” said Meranda Eggebrecht, director of care management and value-based care, Marshfield Clinic Health System. “Antigen tests usually provide results faster than molecular tests, but antigen tests have a higher chance of missing an active infection. At-home tests are a type of COVID-19 test where you collect your own sample and process your sample at home. These tests are not supervised by a health care professional and are not sent to a lab for processing.”

A second COVID-19 test can be necessary to confirm the antigen test results. You should take this test within 48 hours of the original test.

How to determine if you need to re-test

“It is important to get tested if you have symptoms or have been exposed,” Eggebrecht said. “However, testing is not recommended within 90 days of a positive COVID-19 test unless you were COVID-19 positive with recovery of symptoms, and now have new symptoms 30 days or more from the original positive COVID-19 test.”

View or print this handout to help determine if you need to re-test.

• If you have symptoms and:
  • Test positive with an at-home test. No retest is needed. You should follow proper isolation recommendations.
  • Test negative with an at-home test, retest with a PCR test. If the PCR test is positive, follow proper isolation recommendations. Wear a mask until you no longer have symptoms if negative.
• If you do not have symptoms and:
  • Test positive with an at-home test. No retest. You should follow proper isolation recommendations.
  • Test negative with an at-home test. No retest.
• If you have been exposed to COVID-19, wait five days after your exposure before you test, and if you:
  • Test positive with an at-home test. No retest. You should follow proper isolation recommendations.
  • Test negative with an at-home test. No retest. If you are fully vaccinated, you do not need to quarantine. If you are not fully vaccinated, quarantine for five days. Regardless of vaccination status, wear a mask in public indoor spaces for 14 days.

Visit dhs.wisconsin.gov/testing for more information.

How to get a PCR test

You can call your nearest health care location or contact the Nurse Line at Marshfield Clinic Health System, at 844-342-6276, to schedule an appointment or find out if testing is appropriate. Click here to learn more about COVID-19 testing.

Once you receive a PCR COVID-19 test, be sure to follow our steps while you wait.

Regardless of whether your test is positive or negative, you need to continue to protect yourself and others using the health safety precautions.