Tests can be broken down into two basic categories: Diagnostic and Serology (Antibody)
Diagnostic tests can be used to determine if you have an active coronavirus infection. These tests can be used by your healthcare provider or governing bodies to determine the next steps you should take regarding quarantine or isolation from others. There are two types of diagnostic tests for the detection of SARS-CoV-2: molecular and antigen.
Molecular tests detect viral genetic material which allow the virus to produce proteins and replicate during infection. The most common of these tests are polymerase chain reaction (PCR) tests. Generally speaking, molecular tests are the most sensitive and accurate.
Antigen tests detect specific viral proteins known as antigens. Antigen tests tend to be highly specific but are typically less sensitive than molecular diagnostic tests
*Antigens are the proteins that our bodies use to detect pathogenic material and mount an immune response and produce antibodies. The antibodies produced are specific to the antigen(s) detected and will specifically bind to the antigens to prevent an interaction of the antigen with healthy cells.*
Serology tests detect antibodies produced from the immune response that bind specifically to SARS-CoV-2 antigens. While diagnostic tests detect the presence of virus, serology tests detect the body’s response to the virus. This means that serology/antibody tests should not be used for diagnostic purposes.
*We do not know how long antibodies stay in the body following infection with the virus that causes COVID-19. We do not know if antibodies give you protective immunity against the virus, so results from a serology test should not be used to find out if you have immunity from the virus. The FDA cautions patients against using the results from any serology test as an indication that they can stop taking steps to protect themselves and others, such as stopping social distancing or discontinuing wearing masks.*