An estimated quarter million people in the United States do not know they have HIV, the virus that can lead to AIDS. Unfortunately, HIV can complicate other illnesses such as chronic hepatitis. In fact, infection with the hepatitis C virus (HCV) is more serious in persons with HIV infection. (This is true the other way around, too. HCV infection can interfere with HIV treatment.) Because of this, I think it's better for people with hepatitis to know their HIV status as early as possible because they can then have the greatest chance to take successful control of their lives.
The risk factors are similar for HIV and HCV. For both, injecting drugs are common ways of infection. To a much lesser extent, it is also possible to spread hepatitis C sexually, but this is more likely with HIV. For more information about HIV, start with the HIV/AIDS site. For both HIV and viral hepatitis, while early detection is important, prevention is crucial. Make sure you know and understand how viral hepatitis is spread and how you can prevent infection.