Testing for COVID-19 is one of the best ways to halt the spread of the virus. What are these tests? Who should use them, and when? Let's find out.
Why COVID-19 testing is so important
Detecting COVID-19 isn't always easy, especially when we consider that approximately 15 to 30 percent of people infected with the coronavirus (SARS-CoV-2) are asymptomatic, even though they're still contagious. What's more, the most common symptoms of COVID-19 (i.e., cough, fever, headache, muscle aches, chills) are very similar to viral illnesses such as the flu, the common cold, or gastroenteritis (aka, the stomach flu). Accordingly, differentiating COVID-19 from these other illnesses can be a challenge. To make matters worse, symptoms of the virus typically appear 5 to 7 days after infection (or 2 to 12 days in some cases). That means an infected person can be contagious and spread the virus even before they show symptoms!
So, how do you know if you've been infected? Getting tested for COVID-19 is the only way to know for sure! Once you're clear about your diagnosis, you can work toward three basic goals to fight the virus:
- Protect your friends and family
- Identify adequate treatments
- Avoid contaminating people in your community
Testing therefore helps limit the spread of the virus and determine the number of cases in a given population or area. It also promotes a better understanding of the virus and the pandemic and helps guide public health measures.
Who should get tested, and when?
You should take a COVID-19 test in the following situations:
- You show signs or symptoms that may be associated with COVID-19.
- You've been in close contact with someone who has tested positive (even if you have no symptoms).
- You are returning from or leaving for a trip to another country.
Sometimes, in-clinic testing is reserved for high-priority individuals such as health care workers. In this case, you should take a rapid antigen test that you administer yourself at home. You can get these at pharmacies, subject to availability. Click here to learn more about current screening guidelines in Quebec.
What to do if you test positive for COVID-19
Anyone who tests positive for COVID-19 must isolate at home (or in certain cases, at a hospital) and notify everyone they've been in close contact with. These close contacts will then need to get tested, monitor for symptoms, and self-isolate while they await their results.
If you experience covid-like symptoms but can't get your hands on a test, you must self-isolate and follow the guidelines issued by your provincial public health authority.
What are the different types of COVID-19 tests?
There are two main types of tests: PCR tests (molecular detection of SARS-CoV-2 genetic material) and "rapid" antigen tests (detection of SARS-CoV-2 proteins). Let's take a look at each one.
PCR tests are highly sensitive. They can detect the presence of the virus, and therefore confirm a COVID-19 diagnosis from the earliest stages of infection. Some can also reveal the presence of other respiratory microbes such as influenza. PCR tests are currently considered the gold standard in testing. Their interpretation requires sophisticated equipment and medical expertise, which means they need to be analyzed in a special lab.
Some PCR tests involve taking a sample from inside the nose or throat. Others, which are less reliable, involve collecting a saliva sample (spitting into a tube) or a gargle method. Results are usually available within 24 to 48 hours.
Click here to book an appointment for a PCR test at your local pharmacy.
Rapid (antigen) tests
These COVID-19 tests have two main benefits: they're easy to use and the results are available in under an hour. However, they are less sensitive than PCR tests, which means they're less effective at detecting smaller amounts of the virus. A positive result also needs to be confirmed by a second laboratory test.
For this reason, rapid test results must be interpreted with caution to prevent false negatives and a false sense of security. That being said, rapid testing remains relevant in a number of contexts—for example, if you want to test a large number of people, do frequent tests, or get your results quickly (e.g., at an airport or factory).
Click here to book an appointment for a rapid antigen test at your local pharmacy.
Getting a box of rapid tests you can take at home
Over-the-counter rapid tests are also available at pharmacies for your personal use. However, you'll want to make sure you know how to use them and follow the instructions carefully. You should also keep in mind that it's always better to go to a testing centre if you have symptoms or to confirm a positive rapid test result.
For more information about this service and to reserve a box of tests, please visit this page.
COVID-19 testing: A few things to keep in mind
Let's continue to protect ourselves and fight the virus by remembering the following:
- If you receive a positive PCR test result, a public health official will contact you to ask specific questions about your symptoms, where you've been, and what you've been doing over the past few days. They will also ask whether you were in contact with anyone while you were contagious. This process is normal and required to properly monitor transmission and take appropriate action.
- Even if you are fully vaccinated against COVID-19, you can still contract the virus and spread it to others (although you're at much lower risk, especially for the most severe forms of the illness). For this reason, if you have symptoms or have been in close contact with someone infected with COVID-19, you should still get tested, regardless of your vaccination status.
- Health measures should never be relaxed, even if you are vaccinated, have no symptoms, or recently tested negative for COVID-19.
We're all in this together!