Two Main COVID-19 Tests, Explained

06.04.2020 | 3 min read

Amy Barczy is a former brand journalist who authored content at Blue Cross Blue Shield of Michigan. Prior to her time at Blue Cross from 2019-2024, she was a statewide news reporter for MLive.com. She has a decade of storytelling experience in local news media markets including Lansing, Grand Rapids, Holland, Ann Arbor and Port Huron.

There are two main types of COVID-19 tests. They each have a different method, are searching for different things and don’t tell you the same thing. The results of coronavirus tests are complex, which is why they should be done under the care of a qualified health care professional. The professional can explain and interpret the results and discuss their implications.

Diagnostic test

The diagnostic test for the new coronavirus is conducted by inserting a large swab deep into the back of the nasal cavity on both sides of your nose. The test is searching for the virus’ RNA. A positive test result means you have COVID-19 and can infect others with the virus. Nose swabs are the type of tests being used at hospitals, urgent care facilities, pharmacies and drive-through testing sites.

Antibody test

The test that uses a blood sample to look for antibodies to the new coronavirus is commonly referred to as the “antibody test” or “serologic test.” Antibodies are proteins produced by your blood cells to fight bacteria and viruses. This test can tell you if you’ve been exposed to the coronavirus in the past but cannot be used to diagnose you with an active COVID-19 infection. A positive test result means you are either currently infected or have been infected with COVID-19 in the past and now have antibodies to the virus. A positive test result does not mean you can forgo taking precautions (i.e. you still should wear a mask at the grocery store). It’s still important to protect others from getting the virus you were exposed to. A positive test result could also mean you have or recently had a different strain of coronavirus, like the one that causes the common cold. In that case, you could still be susceptible to COVID-19 in the future. A negative result doesn’t necessarily mean you haven’t been infected with COVID-19. If the test is done too soon after someone has first been infected, the test may produce a false negative because there aren’t enough antibodies to meet the testing threshold. Additionally, there are many different types of antibody tests on the market that are being sold without the typical review process from the U.S. Food and Drug Administration, which means the accuracy of many antibody tests has not been verified. Some urgent care locations in Michigan have begun to offer the antibody test.

Other types of tests

Moving onto the market are self-tests and tests that can be done at home. However, these tests are not widely available, and their accuracy is still uncertain. Researchers are still studying what level of antibodies are needed to produce immunity against the new coronavirus. How long such immunity would last is unknown. More from MIBluesPerspectives:

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