HIV factsheet: Screening and testing

Download the alternative format
(PDF format, 151 KB, 2 pages)

Organization: Public Health Agency of Canada

Date published: November 2019


Offer HIV testing as a component of routine care. Individuals involved in high-risk practices should be screened for HIV at least annually.

Risk factors for HIV infection

The risks of getting HIV are mostly behaviour-based. Individuals at higher risk include those who:

Whom to screen

A comprehensive HIV behavioural risk assessment is not required when offering an HIV test. Consider testing:

In the provision of routine medical care, and in discussion with the client, health care providers should consider whether there is a benefit to an HIV test. Health care providers should take an active approach to testing and offer an HIV test to clients. They should also provide a test to a client who has asked for one.


Health care providers should offer HIV testing when screening for other sexually transmitted and blood-borne infections (i.e., syphilis, chlamydia, gonorrhea, and hepatitis B or C).

Did you know?

In Canada, it is estimated that 14% of people living with HIV are unaware of their infection. Canada supports the UNAIDS 90-90-90 targets to eliminate AIDS as a public health threat by 2030. The first target is that by 2020, 90% of all people living with HIV will know their status.

Signs and symptoms

Individuals may develop mild flu-like symptoms 2 to 4 weeks after becoming infected with HIV. During the window period, antibodies are not detectable, and there are high levels of HIV in blood and genital secretions. Early diagnosis and linkage to care are significant steps in preventing onward transmission. Treatment should be offered upon diagnosis.

Primary acute HIV infection

Upwards of 50% of individuals with acute HIV infection may have non-specific symptoms like fever, fatigue, muscle aches and headache. Misdiagnosis of acute infection is common.

Acute or early HIV infection may account for around 50% of secondary infections (i.e., incident cases).

A fourth generation test can detect HIV infection within 15 to 20 days.


Clinicians should maintain a high index of suspicion for HIV infection, and offer an HIV test to individuals with a non-specific febrile illness and/or a history of high-risk behaviour.

Chronic HIV infection

Chronic HIV infection is often asymptomatic for years.

During this stage, the virus continues to replicate at very low levels. Individuals who are unaware of their infection are at increased risk of negative health outcomes and are more likely to transmit HIV to others.

Late diagnosis of HIV infection

It is estimated that 25% to 50% of individuals are diagnosed late in the course of HIV infection.

Symptoms of late infection include: rapid weight loss, pneumonia, and severe and persistent diarrhea.

Many individuals diagnosed with late HIV infection have had multiple contacts with the healthcare system, during which they were not tested for HIV. Capitalizing on opportunities for HIV screening and testing allows for early diagnosis, linkage to care, and treatment leading to improved health outcomes and decreased
onward transmission.

Additional resources


Footnote *

There is effectively no risk of sexual transmission of HIV when the viral load is < 200 copies/ml.

Return to footnote * referrer

Page details

Date modified: