Rapid Antigen Testing (RAT)

Positive RAT results in community or non-high risk settings do not require PCR/rapid molecular confirmatory testing.

Positive RAT tests do NOT need to be reported to Hamilton Public Health Services.

 Positive results from molecular point-of-care testing results should be considered confirmed cases and no longer require a PCR confirmatory test.  

Rapid testing does not replace public health measures such as symptom screening, physical distancing, masking and hand hygiene.

Rapid testing does not prevent someone from getting COVID-19.

A negative test result does not guarantee that you are not infected with COVID-19 or will not spread it to others. False negatives with POC antigen tests are common. Continue to follow all public health guidance to help prevent the spread.

 The Ministry of Health outlines several distinct uses for rapid antigen tests (RATs), including:

  • Screen testing  
  • One-off, non-routine/infrequent asymptomatic testing
  • For people with symptoms
  • For test-to-work purposes

For people without symptoms as screening

 Screen testing is frequent, systematic testing of people who are asymptomatic and without known exposure to a COVID-19 case with the goal of identifying cases that are pre-symptomatic or asymptomatic.

Screen testing with RATs involves routine testing one or more times per week. Individuals in non-highest risk settings participating in routine asymptomatic RAT testing who have a positive result do not require a PCR/rapid molecular confirmatory test.

One-off, non-routine/infrequent asymptomatic testing

  • If an asymptomatic individual without a known exposure to a COVID-19 case decides to complete a RAT outside of routine screening programs, for example prior to a social event/gathering/visit in a non-highest risk setting, then they should complete it as close to the event as possible (e.g. on the same day, ideally within a few hours of the event).
  • There are limitations to a negative RAT result including:
    • RATs have low sensitivity for COVID-19 in people who are asymptomatic and without a known exposure to a confirmed case of COVID-19.
    • People infected with COVID-19 may test negative for several days before testing positive on RAT. Therefore, a negative test may represent a false negative and the infection status of the individual may change within hours of taking the test.
    • Those with a negative one-off RAT should still follow existing public health measures including masking and limiting contacts.

For people with symptoms

If Rapid Antigen Testing is available to the person with any COVID-19 symptoms (see www.ontario.ca/expose), a RAT may be used to assess the likelihood that symptoms are related to COVID-19.

A positive RAT is highly indicative that the individual has COVID-19, and the individual is required to self-isolate:

  • If the individual is fully vaccinated or is a child under 12 years of age, they should self-isolate for 5 days from symptom onset and until their symptoms have been improving for 24 hours (or 48 hours if gastrointestinal symptoms), whichever is longer in duration.
  • If the individual is not fully vaccinated and is 12 years old or older or if they are immune compromised, they should self-isolate for 10 days from the onset of symptoms, or from the date of their test (whichever was earlier).
  • All household members of the positive RAT individual, regardless of vaccination status, should stay at home while the symptomatic individual is isolating (for at least 5 days from symptom onset AND until they do not have a fever and their symptoms have been improving for 24 hours (or 48 hours if gastrointestinal symptoms)) due to the high rate of transmission within households. If they develop symptoms they should follow isolation directions for symptomatic individuals and if eligible for testing, seek testing. More information is available online at www.ontario.ca/expose.
  • If two consecutive RATs, separated by 24-48 hours, are both negative, the symptomatic individual is less likely to have COVID-19 infection, and the individual is advised to self-isolate until symptoms are improving for at least 24 hours (or 48 hours if gastrointestinal symptoms). The household members of the symptomatic individual with two negative tests may also discontinue self-isolation.
  • If the symptomatic individual works in a highest risk setting, they should avoid work for 10 days from symptom onset. If RAT is available, these individuals can return to work on day 7 from the date of symptom onset or positive test (molecular of PCR) (whichever is earlier) if they meet the following criteria:
    • Have two consecutive negative RATs at least 24 hours apart (e.g. day 6 and 7) AND
    • Their symptoms have been improving for at least 24 hours (or 48 hours if gastrointestinal symptoms)
  • In the community non-high risk setting positive RATs do NOT need to be confirmed by PCR/rapid molecular test.
  • Positive RAT tests in the community do NOT need to be reported to Hamilton Public Health Services. Highest risk settings should notify PHUs of a positive RAT result, if the positive individual does not go for PCR confirmation. PCR confirmation of RAT in highest risk is not required, however to allow for timely investigation, the workplace should notify public health.

For test-to-work purposes in highest risk settings

Test-to-work is a strategy to support work-self isolation to meet critical workforce needs for highest risk settings, in which staff are able to return to work when they would otherwise be on self-isolation at home.

Highest risk settings include:

  • Hospitals and health care settings, including complex continuing care facilities and acute care facilities
  • Congregate living settings, e.g. long-term care homes, retirement homes, First Nation elder care lodges, group homes, shelters, hospices, temporary foreign worker settings, and correctional institutions
  • First Nations, Inuit, Métis communities

 Follow directions from your employer occupational health and safety and local health unit guidelines.

For employers or organizations providing private POC testing

  • Organizations (i.e., workplaces) that participate in rapid testing assume any operational, medical, and/or legal responsibilities relating to this initiative.
  • The Hamilton Chamber of Commerce is offering free rapid testing kits for Small and Medium Businesses (with fewer than 150 employees). Details: www.hamiltonrapidtests.ca

Frequently asked questions

The Government of Canada is working with pharmacies to make test kits available for a cost at several locations in Ontario.

The Provincial Antigen Screening Program (PASP) provides free rapid antigen test kits to high-risk communities, organizations and workplaces. Check eligibility.

The program is available to all organizations that are permitted to open and require employees to be physically present on site at the workplace. Organizations mandated to test through a provincial vaccine policy such as Directive 6 are also eligible.

Businesses with fewer than 150 employees can order free rapid antigen test kits for their businesses through the Hamilton Chamber of Commerce. Businesses with over 150 employees can order directly from the Ontario government .  

Rapid testing kits can be obtained:

Individuals who have previously been diagnosed with and cleared of COVID-19 infection may resume asymptomatic screening testing 30 days after their COVID-19 infection (based on the date of their positive result).

Waste from COVID-19 Rapid Antigen Test Kits that are being used at home should be double bagged and may be disposed of in a garbage container.

If this biomedical waste is being generated by a property which is ineligible for municipal collection, then it would need to be collected through a private waste hauler. Examples of ineligible properties would include medical facilities/large clinics, schools, and institutional facilities.

For further information, call 905-546-CITY (2489)

Workplaces should follow provincial guidance for waste disposal.

Positive RAT results in community or non high-risk settings do not require PCR/rapid molecular confirmatory testing and should be considered as true positives. Individuals with positive RAT results should self-isolate immediately and follow these instructions.

If you fail a self-screening tool or receive direction to self-isolate (e.g. have symptoms or are a household contact) you are still required to self-isolate even if your RATS test is negative.

A negative result on a single test cannot rule out a COVID-19 infection by itself. If you have symptoms, take a second test 24 to 48 hours later, if available. If your second test taken within 48 hours of your first negative result is also negative, this most likely means you do not have COVID-19. After your second negative test, continue to isolate until you do not have a fever and symptoms are improving for at least 24 hours (or 48 hours if gastrointestinal symptoms).

Rapid antigen tests are more likely to produce a false negative than a false positive result, i.e. it is more likely that the test will show that you don’t have COVID-19 when you do have it than report that you do have it when you don’t.

If a rapid antigen test comes back as positive it is usually because there is a significant viral load that could be detected (the person is infectious).

For individuals who are eligible, a positive rapid antigen test should be followed up with a confirmatory PCR test. For individuals who not eligible for PCR testing, a positive result on a RAT test should be viewed as a true positive result.

Positive RAT tests do NOT need to be reported to Hamilton Public Health Services.

Additional resources