HIV in Canada: A primer for service providers


HIV Testing and Diagnosis

Key Points

  • An estimated 14% of people with HIV in Canada are not aware of their infection.
  • The earlier the HIV diagnosis, the better the chance to improve or maintain health.
  • Once diagnosed with HIV, people are significantly more likely to take steps to protect their partners from acquiring HIV.

HIV testing and diagnosis is the entry point to HIV treatment, care and support for people living with HIV. It is also a gateway to enhanced engagement in HIV prevention, care and support for people who test HIV-negative but are at ongoing high risk of transmission.

In Canada an estimated 14% of the 63,110 people with HIV in Canada were not aware of their infection in 2016. This group represents a hidden population that may account for more than 50% of new infections, particularly among people who are newly infected and have high viral loads. We also know that some people in Canada are being diagnosed late in their infection. All of this has implications for both individual and public health.

Individual health benefits of an HIV diagnosis can include access to HIV care and treatment as early as possible in the course of the infection, preventative treatment for opportunistic infections, and treatment of sexually transmitted infections (STIs). Clients can also be connected to other services to help address identified issues, for example mental health and harm reduction services or housing programs. For people who test positive, the earlier the diagnosis of HIV is made, the better it is for their health.

HIV diagnosis as early as possible can also have public health benefits. We now know that people with HIV who are on treatment and achieve a sustained undetectable viral load will not transmit HIV to their partners sexually. They are also significantly less likely to pass HIV through other modes of transmission (e.g., shared drug use equipment). Research has shown that when people know they have HIV they are more likely to take steps to protect their partners from HIV than when they are unaware.

For people who test negative and are at ongoing high risk of HIV, testing can link them to HIV prevention supports (such as pre-exposure prophylaxis), or other care and support services such as mental health and harm reduction.

All HIV tests have a window period, which is the time between exposure to HIV and the point when the test can accurately detect and diagnose HIV. The window period varies depending on the test used.

The standard HIV screening test used in Canada is the fourth-generation HIV test. This test screens for both HIV antibodies and the virus itself (specifically, it looks for an HIV protein called the p24 antigen). These antigen–antibody combination tests are sensitive and have a window period of 18 days for 50% of people; 34 days for 95% of the population, and one and a half months for 99% of the population. In this approach a sample of a person’s blood is taken from a vein and sent to a laboratory for HIV screening and, if positive, confirmatory HIV testing. The person must return to the place where they were tested to receive the result.

Rapid point of care (POC) testing, another technology, can improve access to testing because the testing process (including pre-test counselling, receipt of the test result and post-test counselling) takes about 20 minutes. The window period for this test can be as long as three months because the test only looks for HIV antibodies. To test for HIV, a sample of a person’s blood is taken from a finger prick and tested immediately for HIV at the location it was taken. The result may be non-reactive (negative) or reactive (likely positive). If the test is reactive, then a second blood sample is taken from a vein and sent to the laboratory for confirmatory testing. POC testing is currently only available in some provinces.

There is increasing interest in using dried blood spot (DBS) testing in Canada. This approach uses a sample of blood from a finger prick that is collected as a blot on a card. The blood spot is dried at room temperature and mailed to a public health laboratory for screening and confirmatory testing. Currently, this collection technique is in limited use in Canada because very few public health laboratories can process the DBS cards. DBS testing has the advantage of being able to be used in rural and remote areas because the samples are very stable once collected and do not need to be refrigerated. Samples can also be collected by non-medical staff. Dried blood spots can also be used to test for other blood-borne infections, including hepatitis B and hepatitis C.

The standard confirmatory test used in Canada is the Geenius™ HIV-1/2 Confirmatory Assay.

In Canada, HIV testing may be available in three forms:

  1. Nominal testing is the most widely used method of HIV testing. The name of the person being tested and identifying information are sent to the laboratory with the sample, and test providers are legally obligated to report HIV-positive results to public health officials.
  2. Non-nominal testing is similar to nominal testing except the service provider uses a code when sending a sample to be tested. Public health officials are only notified of the identity of the person tested if the result is positive.
  3. Anonymous testing entails no collection of any personal identifying information about the person being tested. Only epidemiological data are sent to public health officials, regardless of whether results are positive or negative.

If someone tests positive for HIV in Canada, it is a legal requirement that public health officials be notified. However, each province and territory has public health laws that stipulate specific requirements for that jurisdiction. Most jurisdictions also have a requirement that an attempt should be made to trace and notify any sexual or drug-sharing partners that may have been put at risk for HIV infection. There are three approaches to partner notification. The HIV-positive person can notify partners of their potential exposure to HIV, a public health practitioner can notify the partners or a combination of these approaches can be used. In cases where the public health practitioner notifies, the name of the person who tested positive is not provided to contacts.

In 2013, the Public Health Agency of Canada released guidelines that include recommendations to address barriers to testing and to improve HIV testing in Canada. The guidelines acknowledge that targeted testing among populations at highest risk of HIV infection needs to continue but that this approach should be complemented with a less targeted testing approach among populations that may be perceived as being at lower risk. A major recommendation in the guidelines is that care providers take a more active approach and offer HIV testing to patients as part of routine medical care, whether or not they have asked for a test. The guidelines also encourage care providers to use a flexible approach and tailor the extent of pre- and post-test counselling to each client’s unique needs and situation, although providing extended counselling is preferred. More specifically, the guidelines state that briefer counselling may be more appropriate for certain clients or patients, such as pregnant women in labour, well-informed patients and people who have already received counselling with a prior HIV test. Whatever the strategy used, HIV testing must be performed only after consent is given that is explicit, informed and voluntary.

The testing guidelines also encourage the integration of HIV testing into other services, particularly those that test for infections that can be transmitted the same way as HIV and/or negatively affect the health of people living with HIV, such as hepatitis C and STIs. Integrating HIV testing into these other services provides additional opportunities to test for HIV and identify undiagnosed individuals.

The guidelines also see HIV testing as an important opportunity to educate individuals at risk of acquiring HIV and those who are newly diagnosed and link them to additional services. For example, all people tested for HIV, regardless of their results, should be provided with information and linked to services to help them reduce their risk of acquiring or transmitting HIV. Therefore, in preparation for HIV testing, the guidelines suggest that providers contact care and support organizations to obtain referral resources for clients. Research shows that people with HIV who are linked to and engaged in care have better health outcomes than those who are not. Therefore, newly diagnosed individuals should be actively linked to care and treatment services, such as an infectious disease specialist who treats HIV.

In 2012, the U.S. Food and Drug Administration approved the first HIV self-testing kit for sale in pharmacies. In Canada, no self-testing kit has been approved by Health Canada but a self-test is expected to be approved by early 2020.


HIV Screening and Testing Guide – Public Health Agency of Canada

The HIV testing process – CATIE fact sheet

HIV testing technologies – CATIE fact sheet

Task-shifting in HIV testing servicesPrevention in Focus

New HIV testing approaches – CATIE Programming Connection webinar


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