Testing for human immunodeficiency virus (HIV) is recommended for individuals with behavioural or epidemiological risk factors, and those who present with clinical indicator conditions. Routine testing is recommended in pregnancy and as part of symptomatic and asymptomatic sexually transmissible infection check-ups. In Australia, laboratories primarily use combined HIV antibody and antigen tests for diagnostic testing. A reactive test is followed by a laboratory confirmatory test. Clinicians should consider whether the person is within the testing window period when interpreting results. On receipt of a confirmed HIV-positive result, healthcare providers must discuss the result and contact tracing with the patient, and ideally refer them to specialised services, including an HIV care provider.