COVID-19 Testing: Good Advice from the Good Doctor

What tests are currently available at North Memorial Health for COVID-19?

“The PCR test is probably the one you’re most familiar with. This test involves a swab to take a sample from your nasal cavity,” says Dr Croston. “A PCR test can provide evidence of a current infection, whether you have symptoms or not.”

In addition, North Memorial Health recently introduced an antibody test available directly to consumers. “The antibody test, also called a serology test, can tell us if someone has been exposed to the virus in the past,” Dr. Croston adds. “Rather than a nasal swab, the antibody test is done by drawing a sample of your blood that is then sent to the lab for testing.”

When should I get a PCR test?

Anyone experiencing one or more symptoms of COVID-19 that may include fever, cough, shortness of breath or difficulty breathing, or who has had known exposure to someone diagnosed with COVID-19 should be tested as soon as possible. Dr. Croston says that “unlike some other COVID-19 testing providers, PCR tests are administered at our walk-up and drive-thru test sites for anyone who requests one, regardless of whether they have symptoms.” He adds that PCR tests do not require a physician referral or appointment at our drive-thru and walk-up sites, and they are billed to your insurance provider. If you do not have insurance, the test may be covered under the CARES Act.

Why should I consider getting an antibody test?

“Many people suspect they may have already had COVID-19, and the new antibody test provides a definitive answer to that question,” says Dr. Croston. North Memorial Health offers the Siemens SARS-CoV-2 total antibody test, one of the most accurate serology tests available today. Positive tests are 96.5% accurate, while negative tests are 100% accurate as long as the test is performed at least 14 days after the onset of symptoms.

“That means if you test negative for antibodies, it’s very unlikely you have had a previous COVID-19 infection,” says Dr. Croston. “In addition, there’s less than a 4% chance of a false positive. So, a positive result, also called a reactive result, indicates that you’ve been exposed to the virus and had an antibody response.”

For people who do test positive, there is another very important point to remember. Patients with a positive result from this the SARS-CoV-1 antibody test may be eligible to become a convalescent plasma donor. “We know that convalescent plasma therapy can help people who have become seriously ill from COVID-19,” says Dr. Croston. “If you’re eligible to become a convalescent plasma donor, you could literally save someone’s life.”

What CAN’T the antibody test tell me?

“A positive antibody test does not mean you can’t get COVID-19 again,” counsels Dr. Croston. “We still don’t know the quantity of antibodies that are necessary to prevent against a new infection and we don’t know how long immunity can last. A positive antibody test doesn’t mean you are immune.” He adds that it also doesn’t mean you aren’t still currently infectious if you’re close to the onset of symptoms, and it’s possible you still could transmit the virus to others.

For these reasons, Dr. Croston advises that a positive antibody test must not change anyone’s safety practices. “No matter the result, everyone should continue to practice social distancing, wear a mask in public areas, and wash their hands frequently,” he says. Antibody tests help us inform individuals about whether they’ve had COVID-19, they help with learning more about the disease and they help us find new donors for convalescent plasma therapy. They do not indicate that people are immune.

Should I ever have BOTH a PCR and an antibody test?

Sometimes patients may come to the ED weeks after their illness began. For these patients, PCR tests may not be as reliable, and the serology test can be used to diagnose an acute COVID-19 illness. “Results from PCR tests may vary depending how long someone has been experiencing symptoms. For those people, the antibody test can also help us confirm a positive diagnosis for the virus,” says Dr. Croston, who adds that in those situations your doctor will be the one to determine whether or not you should get the antibody test.

How can I get the new antibody test?

Patients 18 years of age and older can schedule a SARS-CoV-2 total antibody test through MyChart. Appointments are available three days a week at our Robbinsdale location and two days a week at our Maple Grove location. Patients will receive their results within two to three days. This test is not typically covered by insurance and costs $53.

The Good Doctor's 6 Tips for COVID-19 Testing

1. If you are experiencing one or more symptoms of COVID-19, or you have been exposed to someone who has had a positive COVID-19 diagnosis, it’s critical to get tested as soon as possible. The PCR test will be administered via nasal swab to get a nasopharyngeal sample to look for a current infection.
2. If you believe you’ve already had COVID-19 you can schedule an appointment to receive a SARS-CoV-2 total antibody test. This is a blood test that looks for the presence of antibodies and can tell us if you’ve been previously exposed to COVID-19.
3. To be effective, the antibody test must be given at least 14 days after the onset of symptoms. At that point, a negative result will be 100% accurate.
4. A positive antibody test does not mean you cannot be infected with COVID-19 a second time. We do not yet know how people achieve immunity from the virus, or how long immunity might last.
5. No matter what your antibody test results are, continue to practice good safety measures like social distancing, wearing a mask in public places, and washing your hands frequently to protect your health and the health of those around you.
6. If you test positive for antibodies to COVID-19, consider becoming a convalescent plasma donor. For more information becoming a convalescent plasma donor visit Memorial Blood Centers.