he use of Health Canada authorized COVID-19 antigen tests has become more widespread across the country in recent months. This type of test quickly and easily detects the presence of COVID-19 viral antigens in nasal secretions using a very simple nasal swab. Furthermore, rapid antigen tests have several important advantages – they are less expensive than Nucleic Acid Amplification Tests (NAAT), like RT-PCR tests, and provide results much faster, since the test sample does not need to go to a laboratory for testing.
However, there is still some confusion around their use and interpretation of results. Here is a quick guide on how to use antigen tests and what to do after you get your result.
How long does it take to get results?
Although antigen tests can vary and it is important to follow the instructions provided on the box, most take 15 minutes to provide the result.
Does this test hurt?
Swabbing your nose for a rapid antigen test should not hurt. If it hurts, you may be placing the swab too far into the nose or more forcefully than needed. You may feel some discomfort, but the process is quick and only lasts a few seconds.
What are the components of an antigen test kit?
Usually, each antigen test contains written instructions, a sterile swab, extraction buffer in a tube or vial with a dropper tip and a test cassette. It is essential to read the test instructions first to ensure you get accurate results.
How do I administer the test?
First, it is important to wash your hands and read the instructions contained in the test box and place all the test components on a clean surface. Then, follow these simple steps:
1. Open the extraction tube and place it in the holder (if provided). Some vials come pre-filled with liquid, while others need to be filled with the liquid.
2. Remove the swab from the wrapper while avoiding touching the swab tip.
3. Blow your nose forcefully, then insert the swab into your nostril at a depth of about 2 cm and roll it 5 times in the nostril.
4. Using the same swab, repeat the previous step in the other nostril.
5. Insert the swab into the tube with the liquid, for as long as the instructions specify, so that the buffer can extract the sample from the swab.
6. Remove the swab from of the tube and close the tube with the cap provided.
7. Place the recommended number drops of the liquid into the testing device and wait the recommended amount of time written on the instructions leaflet (typically, about 15 minutes).
8. Read the results appearing on the test device.
How do I read the results?
It is important to read the instruction leaflet that came with the test to find out how the results are displayed. There are 3 types of antigen test results: Positive, Negative, and Invalid.
What to do if you got a positive result?
If you get a positive result, it is important to self-isolate and take an RT-PCR COVID-19 test to confirm the positive result of the antigen test.
What to do if you got a negative result
A negative antigen test result does not completely rule out COVID-19 infection. If you have any symptoms, you should still isolate. If you test negative and have no symptoms, you should follow your local public health guidelines.
Are the antigen test results accurate?
Currently, NAAT-based tests are the most accurate way to test for an infection of the coronavirus, since it is able to detect small amounts of the virus. In contrast, rapid antigen tests reveal when an individual is at the “peak” of COVID-19 infection when the viral load is at its highest, approximately 5-10 days after infection.