2 types of testing look for COVID-19 infections new and old

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Taiwan McCall, left, useless a nasal swab to test James Reese for COVID-19 in the Harlem section of New York, Monday, April 20, 2020. While many laboratories and companies are now offering tests, there are still only two main types available. The nasal swab test tells you if you have an active viral infection right now. A separate blood test tells you if you were previously exposed to the virus and fought off the infection. (AP Photo/Seth Wenig)

WASHINGTON – Testing is critical to controlling the coronavirus and eventually easing restrictions that have halted daily life for most Americans. But there's been confusion about what kinds of tests are available and what they actually measure.

There are still just two main types in the U.S. One tells you if you have an active infection with the coronavirus, whether you have symptoms or not. The other checks to see if you were previously infected at some point and fought it off.

Currently, almost all testing in hospitals, clinics and drive-thru sites uses the first testing method, to help doctors detect and treat people with active COVID-19.

The other method — known as antibody testing — is still getting rolling. But eventually experts predict the blood test will play a key role in allowing many Americans to safely return to work and school by identifying those who are likely immune from the virus.

Neither test can be done at home yet.

Here's a look at both tests and how they work:


Genetic testing is the best method for detecting active COVID-19 infections and making a diagnosis. The process requires several steps and high-tech testing equipment to detect tiny traces of the virus that causes COVID-19.