COVID-19 Testing 101

January 2021

There are currently a few different types of COVID-19 tests available in the U.S. Some tests aim to tell if you are currently infected with the SARS-CoV-2 virus, the virus that causes COVID-19. Others look for signs that you’ve had COVID-19 in the past.

Here’s what you need to know about the available options for COVID-19 testing.

What is the difference between viral/diagnostic testing and antibody testing?
Viral or diagnostic testing can tell if you are currently infected with the SARS-CoV-2 virus. Antibody testing can tell if you may have been exposed to the virus in the past. Below you’ll find answers to common questions about COVID-19 diagnostic and antibody testing.

COVID-19 Diagnostic Testing

What are the different types of COVID-19 diagnostic tests available?
There are currently two main types of COVID-19 diagnostic tests available: molecular tests, also known as polymerase chain reaction (PCR) tests, and antigen tests. Molecular tests check for the presence of SARS-CoV-2 genetic material, while antigen tests check for the presence of a particular protein found on the SARS-CoV-2 virus.

According to the U.S. Food and Drug Administration (FDA), the molecular tests are the most accurate. Many (though not all) molecular tests use PCR to detect genetic material from the SARS-CoV-2 virus.

Depending on the type of molecular test used, the testing sample may be collected by a nasal swab, a throat swab or a swab of the part of the throat behind the nose. Sometimes patients can receive test results within one day. Other times, it can take up to a week to get results or possibly even longer if you’re in an area where labs have a backlog of tests to process.

By contrast, the FDA reports that at least some antigen tests can deliver results within 15 to 30 minutes. These are known as rapid antigen tests. Most of these tests are performed as a swab of the nose or the part of the throat behind the nose. Unfortunately, antigen tests are less accurate than molecular tests. While the FDA reports that a positive test result is typically highly accurate, a false negative is possible. This means that antigen testing may miss some cases of current infection with the SARS-CoV-2 virus.

Who should get tested for COVID-19?
The Centers for Disease Control and Prevention (CDC) recommends that the following people get tested for active infection with the SARS-CoV-2 virus:

  • People who currently have COVID-19 symptoms.
  • People who have had close contact with someone who has tested positive for COVID-19. The CDC defines close contact as being within six feet of someone for 15 minutes or more during a 24-hour period.
  • People who have engaged in activities where they couldn’t maintain social distance. Examples include public travel (e.g., by airplane, bus or train) or attending a large social gathering (indoors or outdoors).

Where can I get a COVID-19 diagnostic test?
Contact your state health department to see where there are COVID-19 testing sites in your area. You can also contact your local pharmacy. Some pharmacies can perform on-site COVID-19 testing.

COVID-19 Antibody Testing

How do COVID-19 antibody tests work?
When you get infected with a virus, your body recognizes the virus as an invader and makes antibodies to fight it. COVID-19 antibody tests look for antibodies in your blood that your body may have produced to fight the SARS-CoV-2 virus. Your body makes antibodies to fight the virus even if you never have any symptoms.

Although these antibodies may provide some level of protection against future infection with the SARS-CoV-2 virus, researchers aren’t sure how much protection the antibodies may offer or how long that protection may last. It’s also possible to get a false positive on this test. So it’s important that you still continue to wear a mask and practice social distancing so you don’t get re-infected or infect anyone else.

How can I get a COVID-19 antibody test?
COVID-19 antibody tests can be done through a blood draw ordered by your doctor or with an at-home blood test.

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