COVID-19 Testing: Molecular, Antigen, and Antibody Tests Explained
There are three types of tests available for COVID-19: molecular, antigen, and antibody (serology) testing. Molecular and antigen tests detect whether a person is currently infected, and serology detects whether a person had an infection in the past. This document is designed to explain the differences between molecular, antigen, and serology testing, and when one test might be used over another.
Diagnostic tests can show if you have an active Covid-19 infection and need to take steps to quarantine or isolate yourself from others. Molecular and antigen tests are types of diagnostic tests than can detect if you have an active COVID-19 infection. Samples for diagnostic tests are typically collected with a nasal or throat swab, or saliva collected by spitting into a tube.
Antibody tests look for antibodies in your immune system produced in response to SARS-CoV-2, the virus that causes COVID-19. Antibody tests should not be used to diagnose an active COVID-19 infection. Antibodies can take several days or weeks to develop after you have an infection and may stay in your blood for several weeks or more after recovery. Samples for antibody tests are typically blood from a finger stick, or blood drawn by your doctor or other medical personnel.
