1. What kinds of coronavirus tests are available? There are two main types of COVID-19 tests: diagnostic tests that detect the presence of the virus in a sample when there’s an active infection and antibody tests, also known as serology tests, which search a blood sample for proteins called antibodies that indicate a previous infection. Diagnostic tests include PCR tests, where a sample from a nasal swab or saliva specimen is processed by a lab so any trace amount of the virus is amplified and detected. Another form of diagnostic testing is antigen testing, also known as a rapid diagnostic test, which detects specific proteins on the surface of the virus.