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COVID-19 Viral Test: About This Test

What is it?

Note: This information is only about the test to diagnose COVID-19. It’s not about tests such as a COVID-19 antibody test that show if you had COVID-19 in the past.

A COVID-19 test is a way to find out if you have COVID-19. It's a viral test that looks for COVID-19 virus in samples (such as swabs) taken from breathing passages, like your nose or throat. There are different types of viral tests:

  • A polymerase chain reaction (PCR) or nucleic acid test looks for genetic material from the virus.
  • An antigen test looks for proteins on the virus.
  • An ID NOW is similar to antigen tests and looks for COVID-19 genetic material in a different way than the PCR test.

The antigen test and the ID NOW are not as accurate (correct) as PCR. People who get an antigen or ID NOW test will need to have 2 swabs collected.

Antigen and ID NOW test results usually come back in a few hours. PCR tests may take a few days. Faster PCR testing or ID NOW testing is done for people who are very sick and need hospital care.

Why is it done?

This test is used to diagnose a current infection with SARS-CoV-2, the virus that causes coronavirus disease 2019 (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 public health experts who track the virus. It can help them learn more about how the virus spreads and how to stop it from spreading.

How do you prepare for the test?

You don't need to do anything to prepare for this test. But be sure to follow any instructions your health care provider gives you.

How is it done?

The test is most often done on a sample from your nose (nasopharyngeal) or throat. One way a sample is collected is by putting a long swab into the back of your nose. If you agree to have an antigen or ID NOW test, you will have 2 samples collected. The first is used for antigen or ID NOW testing. The second is sent to the lab to confirm a negative result with PCR testing or, if the antigen test is positive, test for COVID-19 variants.

What should you do while you wait for your test results?

While you wait for your COVID-19 test results, stay in your home, and stay away from others. This is called isolation or quarantine. 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.

Even if your test is negative, continue to wear a mask and follow physical-distancing guidelines.

What do your results mean?

A PCR result is either positive or negative. An ID NOW or antigen test result is reported as either positive or result to follow.

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

Result to follow means that the antigen or genetic material of the virus wasn’t found in your sample. But your sample needs more testing before confirming the test is negative for COVID-19.

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 may mean that you don't have COVID-19 when in fact you do. This can happen because:

  • You were tested too soon (before the virus got to high enough levels in your nose and throat).
  • You were tested too late (after your immune system fought off the virus).
  • The swab didn’t reach the infected area.

Because a false negative result is possible, continue to isolate if you have symptoms. Follow all public health measures.

For information about when you may need to isolate, go to: COVID-19 Do I Need to Isolate or Quarantine? | Alberta Health Services

Where can you learn more?

Go to

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