The case for early diagnosis of HIV is compelling. Early treatment of HIV (when CD4+ cells are still >200/µl) has several benefits, both for the individual and for public health—it reduces associated morbidity and mortality and greatly reduces the potential for onward HIV transmission.1 Self awareness of HIV seropositivity can be a powerful prevention tool at an individual and community level. Evidence suggests that some people with HIV behave in a less risky manner shortly after they learn they are HIV positive.2 Early diagnosis and treatment is also cost effective, with direct care costs for late presenters (CD4+ cells <200/µl) estimated to be 200% higher than for early presenters.3

Despite medical advances in diagnosing and treating HIV, many people still present late with HIV infection.4 In 2005, about 20 000 residents of the United Kingdom were unaware that they were infected with HIV; almost half of them were men who have sex with men …