What’s The Difference Between Antibody and Molecular Testing?

This is a joint news release issued by the Northern Illinois Rockford Region Public Information Officers (NIR-PIO). NIR-PIO serves Boone, Carroll, DeKalb, Jo Daviess, Lee, Ogle, Stephenson, Whiteside, and Winnebago Counties:

Northern Illinois Rockford Region – There are currently two “rapid” COVID-19 tests available to clinicians in the Northern Illinois Rockford Region. Local health departments want the public to understand the difference between and potential limitations of the two COVID-19 tests.


● Antibody Tests: Using a small sample of blood from a finger prick, the test is designed to detect the presence of antibodies to the SARS-CoV which causes COVID-19. While the test can detect antibodies, it cannot tell you if you are protected from infection, the length of protection against infection, or determine if you have active disease. The test may also detect other coronaviruses that do not cause COVID-19. These tests are promising in determining exposure in the community but are not fully proven.

● Molecular Tests: Using a sample taken from the nasopharynx (nose and throat), a molecular PCR tests determines the presence of active infection with SARS-CoV. This test cannot tell if a person has been exposed and are still in the incubation period before symptoms develop. These test are used to confirm COVID-19 if a person is sick with symptoms of COVID-19.

Both tests require a clinician order and have specific applications and limitations. Employers are encouraged to work with their Employee Health and their local health department for employees who may have been infected with COVID-19, exposed to infection, and/or are returning to work to make sure that they are following the most current evidence-based guidelines.