OHSU Health
A guide to COVID-19 testing
Testing helps in managing the pandemic, so it’s important for everyone to understand the purpose – and limits – of different types of tests.
What is the purpose of COVID-19 testing?
Testing plays a role in stopping the spread of the coronavirus. It does NOT prevent an infection. Please continue to take the measures proven to stop the spread of the virus:
- Limit social gatherings
- Physical distancing
- Regular hand washing
- Wear a face covering
What types of tests are there?
1. Tests to find active coronavirus infections.
These tests involve collecting saliva or nasal mucus. There are two types:
- Molecular. This type looks for genetic material of the virus. It is 85% to 98% accurate. OHSU Health recommends testing no sooner than 3 to 5 days after exposure.
- Antigen. This type looks for a specific protein on the surface of the virus. It is 50% to 95% accurate. This test is most accurate when you have symptoms.
2. Test to find prior coronavirus infections.
This test searches for antibodies in your blood that could mean you’ve been infected with COVID-19 in the past. This type of test may be useful as a way to track the spread of the virus. A positive antibody test does NOT mean you are immune to the virus, and a negative antibody test does NOT mean you have never had COVID-19.
Learn more about each of these tests.
What type of test is best?
It will depend on why you need a test. Whether you have symptoms, a known exposure, or need a rapid result before travel or a medical procedure, be sure to talk with your health care provider.
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