How do I know if I have H I V ? The only way to know if you have HIV or not is to take a test. You can have a free and confidential HIV test at your doctor or local GUM Department (Sexual Health Clinic). If you think you might have been at risk, or if you tested HIV negative a long time ago, go for a test! Knowing whether or not you have HIV allows you to make important decisions about your health and that of others. The sooner you know, the more promtly you can get medical help and give treatments the best chance of working well. For more information about undiagnosed HIV and why it is so important to get tested, click here.