The Eastern Ontario Heath Unit (EOHU) is providing Guidance on the Use of Rapid Antigen Tests as Ontarians access free rapid testing kits for at-home use. While testing supports the province’s cautious easing of public health measures, vaccination remains the best way for individuals to protect themselves, our communities and health care system capacity.

When is it Recommended to Use a Rapid Antigen Test?

Rapid antigen tests are recommended for people with symptoms. If you are symptomatic:

• A positive rapid antigen test is highly indicative that you have COVID-19, and you and your household are required to self-isolate, in accordance with guidance. A confirmatory PCR test or any follow-up testing is not necessary after a positive rapid antigen test. The individual should also reach non-household contacts by providing them with the link to Ontario.ca/exposed.
• A negative rapid antigen test does not rule out COVID-19. Repeat the test 24-48 hours later. If two consecutive rapid antigen tests, separated by 24-48 hours, are both negative, it is less likely that you are infected with COVID-19, and you are advised to self-isolate until symptoms are improving for at least 24 hours (or 48 hours if gastrointestinal symptoms).

Rapid antigen tests are also used for “test-to-work” purposes to meet critical workforce needs in the highest risk settings only.

Rapid antigen tests are not recommended for one-off testing (e.g., before a social gathering) by people who are asymptomatic and without known exposure to someone with COVID-19 as a negative result could be a false negative.

Combined Oral-Nasal Samples

Rapid antigen tests are less sensitive for the Omicron variant compared to the Delta variant in nasal samples, especially in the first 1-2 days after infection. However, the Ontario COVID-19 Science Advisory Table recommends rapid antigen tests can more reliably detect infectious cases of the Omicron variant in combined oral-nasal samples.

Start by reading the instructions that come with your kit. Follow these additional step by step instructions that include swabbing both cheeks, followed by the back of the tongue or throat, and then both nostrils.

For more information about what to do If You Have Symptoms or Have Been Exposed, check out the EOHU’s website at www.EOHU.ca/coronavirus.