Important update: Healthcare facilities
CDC has updated select ways to operate healthcare systems effectively in response to COVID-19 vaccination. Learn more
UPDATE
Given new evidence on the B.1.617.2 (Delta) variant, CDC has updated the guidance for fully vaccinated people. CDC recommends universal indoor masking for all teachers, staff, students, and visitors to K-12 schools, regardless of vaccination status. Children should return to full-time in-person learning in the fall with layered prevention strategies in place.
UPDATE
The White House announced that vaccines will be required for international travelers coming into the United States, with an effective date of November 8, 2021. For purposes of entry into the United States, vaccines accepted will include FDA approved or authorized and WHO Emergency Use Listing vaccines. More information is available here.
UPDATE
Travel requirements to enter the United States are changing, starting November 8, 2021. More information is available here.

COVID-19 Testing: What You Need to Know

COVID-19 Testing: What You Need to Know
Updated May 3, 2022

Types of COVID-19 Tests

COVID-19 tests can detect either SARS-CoV-2 or biomarkers of SARS-CoV-2, the virus that causes COVID-19, or antibodies that your body makes after getting COVID-19 or after getting vaccinated.

Tests for SARS-CoV-2 tell you if you have an infection at the time of the test. This type of test is called a “viral” test because it looks for viral infection. Antigen tests, Nucleic Acid Amplification Tests (NAATs) and other tests are viral tests.

Tests for antibodies may tell you if you have had a past infection with the virus that causes COVID-19. Your body creates antibodies after getting infected with SARS-CoV-2 or after getting vaccinated against COVID-19. These tests are called “antibody” or “serology” tests.

Testing is very important to help reduce the spread of COVID-19. You should always discuss your test results with your healthcare provider.

Viral Tests

A viral test tells you if you are infected with SARS-CoV-2, the virus that causes COVID-19, using samples that come from your nose or mouth. There are two types of viral tests: rapid tests and laboratory tests. COVID-19 testing is one of many risk-reduction measures, along with vaccination, masking, and physical distancing, that protect you and others by reducing the chances of spreading COVID-19.

  • Rapid Point-of-Care tests, test performed or interpreted by someone other than the individual being tested, can be performed in minutes and can include antigen tests, some NAATs, and other tests.
    • Self-tests are rapid tests that can be taken at home or anywhere, are easy to use, and produce rapid results.
  • Laboratory tests can take days to complete and include RT-PCR and other types of NAATs.

Antibody Tests

An antibody test (also known as a serology test) can detect antibodies to SARS-CoV-2 in your blood. Antibodies are proteins that your immune system makes to help fight infection and protect you from getting sick in the future.

Antibody tests should not be used to diagnose a current infection, but they may indicate if you had a past infection. Antibody tests help learn about how human immune systems defend against the virus, as well as learn about population-level protection. If you get an antibody test after receiving a vaccine, you might test positive by some (but not all) antibody tests. This depends on which type of antibody the specific test detects.

Antibody testing is not currently recommended to determine:

  • If you have a current infection.
  • If you have immunity to SARS-CoV-2 following COVID-19 vaccination.
  • Whether you need to get a booster following COVID-19 vaccination.
  • Whether you need to quarantine after a known or suspected exposure to COVID-19.

Need a COVID-19 Test?

Reasons to Get Tested
  • If you have COVID-19 symptoms
  • At least 5 days after known or suspected close contact to COVID-19
  • For screening (schools, workplaces, congregate settings, etc.)
  • Before and after travel
  • When asked by a healthcare professional or public health official
Types of Viral Tests

Laboratory Test

  • Sample can either be a nasal swab or saliva
  • Results usually in 1-3 days
  • Results are reliable for people with and without symptoms
  • No follow-up test required
  • Common example: PCR test

Rapid Test

  • Sample is usually a nasal swab
  • Results usually in 15-30 minutes
  • Results may be less reliable for people without symptoms
  • Follow-up test may be required
  • Common example: Antigen test
Actions After Result

If Positive Result

If Negative Result

  • If up to date on vaccines: return to normal activities. Wear a mask indoors in areas where the COVID-19 Community Level is high.
  • If not up to date on vaccines and have symptoms or exposure: quarantine for at least 5 days.
  • If not up to date on vaccines and have no symptoms or exposure: return to normal activities. Take steps to get up to date on vaccines to protect yourself and others.

Testing Tools

These chatbots ask a series of questions, and provide recommended actions and resources based on your responses.

user md chat light icon

Coronavirus Self-Checker

A tool to help you make decisions on when to seek testing and medical care.

Need additional help? CDC’s Viral Testing Tool is an online, mobile-friendly tool that asks a series of questions, and provides recommended actions and resources based on a user’s responses.

Print Resources
Science at CDC
Scientific evidence and studies behind specific COVID-19 guidance and recommendations

Science BriefsMMWR COVID-19 Reports