HIV factsheet: Types of HIV screening tests
The choice of HIV test may vary depending on clinical evaluation and patient history, including timing to potential exposure.
|Third-generation enzyme immunoassay (EIA) test||Fourth-generation test||Point-of-care tests (POC)|
|The HIV enzyme immunoassay (EIA) test is used to detect antibodies produced in response to HIV infection. Results are reported as reactiveFootnote * or non-reactive. It may take up to 12 weeks for an infected individual to produce detectable HIV antibodies (i.e., the generally accepted "window period"), though some people will have a reactive result with third-generation HIV EIA tests as early as 20 to 30 days after exposure.||This test is the most commonly used test in Canada. It's a combination test that detects both antibodies and the HIV p24 antigen. This test is more sensitive than the antibody test and can detect infection within 15 to 20 days. As many as 95% of people with HIV infection will test positiveFootnote * with a fourth-generation combination test within 34 days; however, the window period can be up to 12 weeks.||HIV POC tests can be used to detect HIV antibodies. Results can be available in several minutes. Positive results from HIV POC tests are considered 'preliminary positive' only and should be confirmed with a standard serology test.|
Window period: In most individuals, antibodies can be detected within weeks of HIV exposure. If the first HIV test is negative and a high-risk exposure occurred less than 12 weeks prior (i.e., during the window period), repeat HIV testing should be offered.
For more information, please consult your local public health laboratory or provincial/territorial guidelines.
Barriers and facilitators of HIV screening and testing
How healthcare providers can facilitate HIV screening and testing
Healthcare providers are encouraged to actively decrease barriers to HIV testing, so that individuals agree to seek testing. Those with negative results can take proactive attempts to protect themselves against HIV infection, and individuals with positive results can be linked to treatment and care.
Barriers to patients seeking HIV testing include:
- fear of positive result and associated stigma
- stigma and discrimination associated with risk behaviours
- lack of perceived risk of HIV infection
- discomfort discussing HIV
To facilitate HIV testing, healthcare providers can:
- assure protection of the client's anonymity and confidentiality
- normalise the offer of HIV testing, making it part of routine medical care
- simplify risk assessments by providing brief information about HIV (i.e., how it's transmitted) and offering a test
- emphasize the benefits of early diagnosis and treatment, which make HIV a chronic manageable condition with a near normal lifespan
- take steps to provide an environment that is free of stigma and discrimination
- provide patients with information on the routes of transmission, risk factors for HIV infection, and other prevention methods (e.g., pre-exposure prophylaxis or post-exposure prophylaxis)
Offering an HIV test
In Canada, HIV testing is voluntary: the client is free to accept or refuse the offer of testing. When offering an HIV test, healthcare providers should ensure the individual understands:
- how HIV is transmitted
- the advantages (i.e., clinical and prevention benefits) and disadvantages of testing
- the right to refuse
- the follow-up services that may be offered
- that public health will be notified in the event of a positive test result
- the public health benefits of disclosing their HIV status to current and future partners in the event of a positive test result, along with the benefits of partner notification to encourage previous and current partners to be tested
Note: Verbal consent is sufficient to proceed with testing. Although informed consent cannot be implied or assumed,
written consent is not necessary.
- Public Health Agency of Canada's HIV Screening and Testing Guide
- Government of Canada: HIV and AIDS for Health Professionals
- Canada Communicable Disease Report: An Overview of Recent Evidence on Barriers and Facilitators to HIV Testing
- Canada Communicable Disease Report: Canadian and International Recommendations on the Frequency of HIV Screening and Testing: A Systematic Review (PDF)
- CATIE - HIV Testing Technologies
Report a problem or mistake on this page
- Date modified: