What Is The Difference Between Antibodies and Antigens?

Jul 9th 2020

Antigens vs Antibodies

As the COVID-19 pandemic continues and testing continues to ramp up to meet society’s needs, understanding the difference between testing methods can help inform us on a strategic approach. Based on our interactions with customers regarding COVID-19 (SARS-CoV-2) testing, it appears that two types of tests are little understood and often mistaken for one another: Antibody Tests and Antigen Tests.

Antibodies are generated by the body’s immune system upon the detection of potentially threatening pathogens. Antibodies are a natural response to a viral infection like COVID-19 and can be a reliable way to track the spread of a disease and even detect whether or not the body is actively fighting a pathogen through the detection of IgM antibodies.

Antigens are molecules from outside the body that trigger a response from the immune system. That antigen molecule could be a viral structure such as COVID-19.

In other words, a test that screens for antibodies is screening for the body’s response to a pathogen and an antigen test is screening for a molecular structure of the pathogen itself. The COVID-19 Antibody Rapid Detection Kit distributed by AllSource Screening Solutions is an antibody test screening for antibodies produced by the body in response to SARS-CoV-2.

Antigen testing for COVID-19 has not yet become a mainstream option to combat the pandemic but these screens are being developed.

Antibody tests are widely available and can be used for tracking the spread of the infection. Tracking the spread of the infection is possible because of the 2 different antibodies that are detectable: IgG and IgM antibodies. IgM antibodies evidence themselves in the body while the body actively fights a viral infection, and IgG antibodies evidence themselves after that body has fought off the virus. IgG antibodies will last in the body long after the virus has been fought off and using those antibodies, it is possible to track the extent to which COVID-19 has spread throughout the population.