There is no legal requirement that you disclose your HIV status before undergoing any type of medical examination or treatment.
However, it may be wise to disclose since HIV medications may interact with other medications; or the progression or treatment of other conditions may be affected by HIV infection. Under such circumstances, failure to disclose may lead to serious or even fatal consequences. Your treatment for other conditions may have to be modified to allow for the effects of HIV infection and HIV medications, and your doctor or dentist can only do this if he or she is fully informed. Discuss with your regular HIV specialist doctor whether disclosure to other practitioners is medically necessary.
If you disclose your HIV status to a medical practitioner, then this information, like other medical information, is protected by the medical profession’s duty of confidentiality.
Source: HIV/AIDS Legal Centre, Sydney http://halc.org.au/publications/guides-to-hiv-and-the-law/