Testing for COVID-19: Test accuracy
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The accuracy and reliability of COVID-19 diagnostic tests is important to inform diagnosis and to ensure Canadians can make the right decisions about their health.
Accurate results mean that Canadians can take preventative measures to protect loved ones and others if they test positive. They can also avoid unnecessary self-isolation and anxiety if they receive a ‘false positive’ result (getting a positive result when you don’t have the virus).
A negative test usually means you don't have COVID-19.
However, the accuracy of a test can vary depending on when your sample is taken during the course of your illness. If you're tested too soon after you were exposed to COVID-19, there may not be enough virus in your body for an accurate result. If this is the case at the time of the test, your test may come back negative, even if you actually have the virus. This would be considered a ‘false negative’ test.
It’s important to understand that health care professionals consider a number of factors in making a COVID-19 diagnosis. Other factors may cause a physician to order another test or even diagnose COVID-19 despite a negative result, such as:
- timing of your test
A positive test means that you have COVID-19 and you must follow the direction of your local health authority.
Sometimes, tests are inconclusive. In this case, your health care provider may re-test you.
When to get tested
Public health authorities in every province and territory have developed their own approaches for testing people based on the local context.
For information about COVID-19 testing in your area, contact your local public health authority.
How to get tested
If you think you might have COVID-19:
- try this self-assessment tool or one of the self-assessment tools available from your province or territory
- connect with your local public health authority, as they can tell you how to get tested
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