What's the difference between a PCR & Antigen test?

There are two types of diagnostic tests for COVID-19: PCR and antigen.

 PCR tests detect the virus's genetic material.

  • PCR are the most accurate tests for detecting the virus that causes COVID-19.
  • They are given with a nasal swab, oral (throat) swab, or by taking a saliva sample.
  • PCR tests are used whether or not you have symptoms.
  • There are at-home versions and point of care versions, as well as versions analyzed in a laboratory. 
  • A positive PCR or other molecular amplification test result is considered a confirmed case of COVID-19.

 Antigen tests look for the presence of specific proteins found on the surface of the virus.

  • Antigen tests typically produce results within 15-30 minutes, more quickly than the PCR test.
  • The preferred test to use immediately before attending events where people may not be distancing or wearing masks. It's also preferred for people who need a negative test to go back to work after having COVID-19, or have recently recovered from COVID-19 and suspect that they may be reinfected.
  • Antigen tests can identify people who are infectious and could spread COVID-19 to someone else. 
  • They may not be as accurate, especially for people who do not have symptoms.
  • Antigen tests are given with a nasal swab.
  • There are at-home antigen tests as well as point of care versions. Some types of antigen tests are analyzed in a laboratory and take longer to get results.
  • A positive antigen test result is considered a probable case of COVID-19. 

 For more information on types of tests, visit the FDA COVID-19 Testing Basics page. 

Show All Answers

1. What are my options for COVID-19 testing?
2. How do I find & use an at-home COVID-19 test kit?
3. What's the difference between a PCR & Antigen test?
4. Who should get tested?
5. When should I get a COVID-19 test?
6. Where can I get a COVID-19 test?
7. What should I do while I wait for my test results?
8. What does my test result mean?
9. What should I do if I test positive?
10. When should I test if I am already in home isolation because I have COVID-19 or am in home quarantine because I was exposed to COVID-19?