Eastern Ontatio Health Unit / Bureau de santé de l'Ontario

Guidance on the Use of Rapid Antigen Tests

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 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. If no instructions were provided, see the links below to learn how to use each variety. 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.

Instructions on how to use each variety of rapid antigen tests being distributed by the province:

Frequently Asked Questions about Rapid Antigen Testing (RAT) and PCR tests

I’m symptomatic and I’ve done a RAT that is positive
I’m symptomatic and I’ve done a RAT that is negative
I’m asymptomatic and I’ve done a RAT that is positive
I’m asymptomatic and I’ve done a RAT that is negative
I’m symptomatic but I tested negative on a PCR. Do I (and my contacts) still need to isolate?

I’m symptomatic and I’ve done a RAT that is positive

  • You are no longer required or encouraged to get a confirmatory PCR or rapid molecular test. It is not necessary to report positive rapid antigen test results to the EOHU.
  • If you test positive from a rapid antigen test or are presumed positive based on your symptoms, see here for isolation instructions.
  • Household contacts of individuals who test positive or are presumed positive based on their symptoms may need to isolate as shown here.  
  • You should also reach your non-household contacts by providing them with the link to Ontario.ca/exposed. Individuals who are eligible for a lab-based PCR test are encouraged to get tested.

I’m symptomatic and I’ve done a RAT that is negative

  • A negative rapid antigen test does not rule out COVID-19. Repeat the test 24-48 hours later. If you complete 2 RATs, separated by 24-48 hours, and both are negative, you may end self-isolation once your symptoms are improving for at least 24 hours (or 48 hours if gastrointestinal). Any household members who may have needed to isolate can discontinue self-isolation, as long as they are asymptomatic.
  • If you are isolating as a high-risk contact of COVID-19, please complete your isolation period.
  • If you are not able to complete 2 RATs, you are presumed positive based on your symptoms and you must follow the direction here. You are no longer required or encouraged to get a confirmatory PCR or rapid molecular test.
  • Household contacts of individuals who test positive or are presumed positive based on their symptoms may need to isolate as shown here.
  • You should also reach your non-household contacts by providing them with the link to Ontario.ca/exposed. Individuals who are eligible for a lab-based PCR test are encouraged to get tested.

I’m asymptomatic and I’ve done a RAT that is positive

  • You are no longer required or encouraged to get a confirmatory PCR or rapid molecular test. It is not necessary to report positive rapid antigen test results to the EOHU.
  • If you test positive from a rapid antigen test or are presumed positive based on your symptoms, see here for isolation instructions.
  • Household contacts of individuals who test positive or are presumed positive based on their symptoms may need to isolate as shown here.
  • You should also reach your non-household contacts by providing them with the link to Ontario.ca/exposed. Individuals who are eligible for a lab-based PCR test are encouraged to get tested.

I’m asymptomatic and I’ve done a RAT that is negative

  • You do not need to self-isolate unless you are isolating because of a close contact requiring you to self-isolate as shown here.

I’m symptomatic but I tested negative on a PCR. Do I (and my contacts) still need to isolate?

  • People who have symptoms that are eligible for testing and test negative on a PCR test may discontinue isolation once symptoms have been improving for 24 hours (or 48 hours for gastrointestinal) unless they have been exposed to someone with COVID-19 or who has symptoms of COVID-19 AND are required to self-isolate as shown here. If you were required to self-isolate as shown here, you must complete your required isolation even with a negative PCR test.

Certain sections of this page were adapted from Ottawa Public Health.

Eastern Ontatio Health Unit / Bureau de santé de l'Ontario