Testing Tips: A negative diagnostic test should not be put to rest!

I received a diagnostic COVID-19 test result, how confident can I be in that result?

  • If you were to receive a positive result on a COVID-19 test, you can be very confident that you are infected with the virus. However, there is much less confidence in a negative test’s ability to identify if someone truly does not have an infection.

Why is there more uncertainty with negative test results? 

A diagnostic test is more likely to give a false negative result if:

  • The test was taken on the day the person was exposed. On the day of exposure or recently after exposure (less than 4-5 days), the amount of virus particles in your body is extremely low and may go undetected on a test.
  • The person is not showing symptoms at the time they are tested. Evidence suggests that COVID-19 tests are more accurate if the person is tested while they have symptoms. 
  • The diagnostic test sample (respiratory swab or saliva) did not detect the virus. An insufficient sample may be taken that did not collect enough of the virus particles to give a positive result.  

If I receive a negative test result, should I get re-tested?

  • Not necessarily. You should only consider getting retested if:
    • You begin to develop symptoms or if your symptoms appear to be getting worse. 
    • You were tested less than 4-5 days after your exposure
    • If you are certain you had close contact with someone who tested positive for the virus.

What should I do if I received a negative test result?

  • Testing is not perfect, so it is important to be cautious and if you are able, self-quarantine for 10 days if you have had close contact with someone who is a known COVID-19 case, particularly if it is a household member, even if your test result is negative.  
  • Presumably, you received a test because you were concerned about the virus and were either experiencing symptoms or had an exposure to someone who tested positive. So it is important to continue taking precautions and note that you may be asymptomatic or presymptomatic even if you have the virus. 
  • If you are experiencing any symptoms, regardless of a negative test result, you should practice social distancing, wear a mask, and avoid returning to work. 
  • During this time you should stay home, maintain physical distancing, and watch for symptoms including taking your temperature each day to ensure it does not go over 100 degrees Fahrenheit (this is a sign of infection), and wear a face covering. 

REMEMBER: you may be exposed to COVID-19 after you have been tested for the virus. Therefore, if you received a negative test result, this result only applies to you at the time you were tested – not at the time you received your result. You could still be infected by COVID-19 in the future and should continue to take safety precautions. Note that test results may take up to a week or more.

Information from this article was drawn from: https://www.health.harvard.edu/diseases-and-conditions/if-youve-been-exposed-to-the-coronavirus

Curious about what a diagnostic test is? To find out more information, please visit this link.

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