High risk: high risk sexual behaviour (known HIV + partner, men who have sex with men, sexual partner who is an injection drug user [IDU] or sex trade worker, or multiple sexual partners); history of incarceration; shared needles or other drug paraphernalia; other STIs; injection drug use; tattoos/body piercing; sexual or blood contact with a known case of HIV; presence of symptoms consistent with an acute seroconversion illness with HIV; or the exposure occurred in a high risk clinic (e.g. HIV clinic).