There are different types of tests – diagnostic tests and antibody tests.
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.
Getting Tested
If you are tested, you should quarantine and isolate yourself at home until you receive your test results and follow the advice of your health care provider or a public health professional.
When should I get a test?
If you have symptoms of COVID-19, even after vaccination
If you have had close contact (within 6 feet for a total of 15 minutes or more) with someone with confirmed COVID-19, even after vaccination
If you took part in activities that put you at higher risk for COVID-19 because you could not socially distance as needed, such as travel, attending large social or mass gatherings, or being in crowded indoor settings
If you have been asked or referred to get tested by your health care provider, or local External Link Disclaimer or state health department
Your school, workplace or community may also establish a screening program, in which they test individuals who are part of a group (at work, at school) even if there is no reason to suspect those individuals are infected with COVID-19. The FDA issued more information about screening programs in this fact sheet.
https://www.cdc.gov/coronavirus/2019-ncov/symptoms-testing/testing.html
