Viral Test for COVID-19

Test Overview

A COVID-19 viral test is a way to find out if you have COVID-19. The test looks for the virus in your breathing passages. There are different types of viral tests.

One type looks for genetic material from the virus. This is usually called polymerase chain reaction (PCR).

Another type looks for proteins on the virus. This is usually called an antigen test. It may not be as accurate as PCR.

Some test results come back in a few minutes. Others may take a few days.

Why It Is Done

This test is used to diagnose a current infection with SARS-CoV-2, the virus that causes COVID-19. Knowing that you have the virus means that you can take steps to protect others from getting infected. This can help limit the spread of the virus.

Knowing who has COVID-19 is also important for experts who track the virus.

How It Is Done

The test is most often done on a sample from your nose or throat. It's sometimes done on a sample of saliva. One way a sample is collected is by putting a long swab into the back of your nose. Samples can be tested in different ways to look for an infection.


The result is either positive or negative.

A positive result means that the antigen or the genetic material of the virus was found in your sample. You have COVID-19 now.

A negative result means that the antigen or the genetic material was not found. This may mean that you don't have COVID-19.

But it's possible to get a "false-negative" result. This means that the test shows that you don't have COVID-19 when in fact you do. This may happen because you were tested too soon after you were infected, before the virus started to spread in your nose and throat. Or it could happen because the swab missed the infection.

If you get a negative result for an antigen test, your doctor may recommend that you get another test, such as polymerase chain reaction (PCR), to make sure you don't have the virus. In general, PCR is more accurate than an antigen test.

Some test results come back in a few minutes. Others may take a few days.

If your test is negative, follow your doctor's advice for when you can go back to activities. If your test is positive, talk to your doctor or a public health official about what you need to do.

Waiting for your test results

If you are being tested because you aren't fully vaccinated and you've been exposed to COVID-19 or have been sick from COVID-19, you will want to know what to do while you wait for your test results. While you wait for the results of your COVID-19 test, stay in the place where you live, and stay away from others. Do this even if you don't feel sick or have any symptoms. Don't leave unless you need medical care. If you can, try to stay in a separate room. This might help you avoid infecting family members or other people you live with.

Follow your doctor's instructions about what to do when you get your results back.

Be sure to wear a mask and follow social-distancing guidelines after you get your results, even if the test is negative.

If you're fully vaccinated and were exposed to COVID-19, wear a mask in public indoor spaces until you test negative for COVID-19.

Related Information


Current as of: March 26, 2021

Author: Healthwise Staff
Medical Review:
Heather Quinn MD - Family Medicine
Lesley Ryan MD - Family Medicine