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URL of this page: https://medlineplus.gov/lab-tests/rapid-tests/

Rapid Tests

What are rapid tests?

Rapid tests, also known as rapid diagnostic tests or RDTs, are easy-to-use tests that provide quick results, usually in 20 minutes or less. Unlike most standard tests, which have to be sent to a lab, rapid tests are done and provide results at the point of care. The point of care is the place where you are getting care. It can include your provider's office, a clinic, or even your own home.

Rapids tests usually include the following steps:

  • You will provide a sample of your body fluid, such as blood, urine, saliva, or nasal secretions.
  • The sample is mixed with a special substance that will cause a chemical reaction if a disease or other condition is present.
  • Results will show on a dipstick or rapid test cassette.
    • A dipstick is a thin, plastic strip that's coated with chemicals. If the test is positive, the dipstick will change colors when placed in the sample.
    • A rapid test cassette is a small, plastic case that has a well that holds the sample. The well will show a letter or a symbol to indicate the result.

Most rapid tests are highly accurate, but the results are not always as accurate as standard lab tests.

Other names: rapid diagnostic tests, RDT's point-of-care tests

How are they used?

Rapid tests are most often used to diagnose infectious diseases, including:

Rapid tests are also used in certain home-based tests, such as pregnancy tests.

What are the advantages and disadvantages of rapid tests?

The advantages of rapid tests include:

  • Fast results. This may allow you to get treatment faster. Faster treatment can reduce the severity of your symptoms, and may help prevent the spread of disease
  • Easy to use. They can be done by non-medical workers and volunteers who have been trained to do the test. You may even be able to perform a rapid test on yourself.
  • Little or no special equipment required. This is especially useful in areas with limited resources or access to specialized labs.

Disadvantages of rapid tests:

  • Lower sensitivity than lab tests. Sensitivity means how well a test can identify a disease or condition. Rapid tests are not as good as lab tests at finding diseases in the earliest stages of infection.
  • False negatives are more common. A false negative result means your test shows you don't have a disease or condition, but you actually do have it.

Providers will often take a second sample and send it to a lab for testing to confirm or rule out the results of a rapid test. But you may be able to get treatment and help prevent the spread of disease while you wait for lab results.

Is there anything else I need to know about rapid tests?

Home based rapid tests are available for COVID-19. Like other rapid tests, the rapid COVID-19 tests have lower sensitivity than standard lab tests. But getting fast, home-based results may help prevent the spread of disease. Talk to your health care provider to learn more about these home-based tests.

References

  1. Centers for Disease Control and Prevention [Internet]. Atlanta: U.S. Department of Health and Human Services; Influenza (Flu): Rapid Influenza Diagnostic Tests; [cited 2021 Jan 26]; [about 5 screens]. Available from: https://www.cdc.gov/flu/professionals/diagnosis/clinician_guidance_ridt.htm
  2. Centers for Disease Control and Prevention [Internet]. Atlanta: U.S. Department of Health and Human Services; Malaria: Rapid Diagnostic Tests: How They Work; [cited 2021 Jan 26]; [about 5 screens]. Available from: https://www.cdc.gov/malaria/malaria_worldwide/reduction/dx_rdt.html
  3. Emory University [Internet]. Atlanta: Emory University; c2020. What is Rapid Diagnostic Test (RDT)?; [cited 2021 Jan 26]; [about 3 screens]. Available from: http://www.globalhealthprimer.emory.edu/targets-technologies/rapid-diagnostic-test.html
  4. FDA: U.S. Food and Drug Administration [Internet]. Silver Spring (MD): U.S. Department of Health and Human Services; Coronavirus (COVID-19) Update: FDA Authorizes Antigen Test as First Over-the-Counter Fully At-Home Diagnostic Test for COVID-19; 2020 Dec 15 [cited 2021 Jan 26]; [about 3 screens]. Available from: https://www.fda.gov/news-events/press-announcements/coronavirus-covid-19-update-fda-authorizes-antigen-test-first-over-counter-fully-home-diagnostic
  5. FDA: U.S. Food and Drug Administration [Internet]. Silver Spring (MD): U.S. Department of Health and Human Services; Coronavirus (COVID-19) Update: FDA Issued Emergency Use Authorization for Point of Care Antigen Test; 2020 Jul 6 [cited 2021 Jan 26]; [about 3 screens]. Available from: https://www.fda.gov/news-events/press-announcements/coronavirus-covid-19-update-fda-issued-emergency-use-authorization-point-care-antigen-test
  6. GoodRx [Internet]. GoodRx, Inc., c2011–2021. COVID-19 Rapid Tests: Accuracy, Types, and Where to Find Them; 2020 Nov 10 [cited 2021 Jan 26]; [about 3 screens]. Available from: https://www.goodrx.com/blog/covid-19-rapid-test
  7. Harvard Health Publishing: Harvard Medical School [Internet]. Boston: Harvard University; 2010–2021. Rapid Strep Test; 2019 Dec [cited 2021 Jan 26]; [about 4 screens]. Available from: https://www.health.harvard.edu/diseases-and-conditions/rapid-strep-test
  8. Mayo Clinic [Internet]. Mayo Foundation for Medical Education and Research; c1998–2021. COVID-19 Diagnostic testing: Overview; 2021 Jan 15 [cited 2021 Jan 26]; [about 3 screens]. Available from: https://www.mayoclinic.org/tests-procedures/covid-19-diagnostic-test/about/pac-20488900
  9. Mayo Clinic [Internet]. Mayo Foundation for Medical Education and Research; c1998–2021. Urinalysis: Overview; 2019 Oct 23 [cited 2021 Jan 26]; [about 3 screens]. Available from: https://www.mayoclinic.org/tests-procedures/urinalysis/about/pac-20384907
  10. Poole S, Townsend J, Wertheim H, Kidd SP, Welte T, Schuetz P, Luyt CE, Beishuizen A, Jensen JS, Del Castillo JG, Plebani M, Saeed K. How are rapid diagnostic tests for infectious diseases used in clinical practice: a global survey by the International Society of Antimicrobial Chemotherapy (ISAC). Eur J Clin Microbiol Infect Dis [Internet]. 2021 Feb; [cited 2021 Jan 26]; 40(2):429–434. Available from: https://pubmed.ncbi.nlm.nih.gov/32902760
  11. P.vivax information hub [Internet]. Medicines for Malaria Venture; Rapid Diagnostic Tests (RDTs); [cited 2021 Jan 26]; [about 3 screens]. Available from: https://www.vivaxmalaria.org/diagnosis-treatment/diagnostic-methods/rapid-diagnostic-tests-rdts
  12. ResearchGate [Internet]. ResearchGate GmbH; c2008–2021. Example of RDT Cassettes; [cited 2021 Jan 26]; [about 3 screens]. Available from: https://www.researchgate.net/figure/Example-of-RDT-cassettes-Most-of-the-cassettes-have-separated-wells-for-sample-and_fig2_49830148
  13. Very Well Health [Internet]. New York: About, Inc.; c2021. An Overview of Specificity and Sensitivity; [updated 2020 Sep 27; cited 2021 Jan 26]; [about 3 screens]. Available from: https://www.verywellhealth.com/sensitivity-and-specificity-in-medical-testing-overview-4777799
  14. Very Well Health [Internet]. New York: About, Inc.; c2021. Why Your Rapid Flu Test Was Negative; [updated 2020 Apr 2; cited 2021 Jan 26]; [about 3 screens]. Available from: https://www.verywellhealth.com/why-was-my-flu-test-negative-770309
  15. World Health Organization [Internet]. Geneva (SUI): World Health Organization; c2021. Advice on the use of point-of-care immunodiagnostic tests for COVID-19; 2020 Apr 8 [cited 2021 Jan 26]; [about 4 screens]. Available from: https://www.who.int/news-room/commentaries/detail/advice-on-the-use-of-point-of-care-immunodiagnostic-tests-for-covid-19#
  16. World Health Organization [Internet]. Geneva (SUI): World Health Organization; c2021. Simple/Rapid Tests; 2014 Jun 27 [cited 2021 Jan 26]; [about 3 screens]. Available from: https://www.who.int/news-room/q-a-detail/simple-rapid-tests

The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.