Background Intravenous drug users, particularly those in prison, are at high risk of acquiring HIV and Hepatitis C (HCV) and commonly do not access mainstream medical care. Missed opportunities for HIV and Hepatitis C testing in Intravenous drug users attending prisons are therefore common. By using oral swabs difficulties of venous access can be avoided. Lambeth has the highest prevalence of HIV in the UK and it is estimated that 15–20% of inmates at HMP Brixton are HIV positive.

Methods Staff delivered 26 walk-in clinics at a drug rehabilitation unit in Brixton over 5 months. The testing service was developed in close liaison with the drug and alcohol team and publicised using posters and education of reception staff. Oral swab testing for HIV and HCV was offered. A simple questionnaire was completed by attendees covering testing history and risk practice.

Results 35 individuals tested for HIV and HCV and were 80% male, 74.3% UK born, 48.6% white and 77.1% heterosexual. 37.1% were IVDU, median age was 36 (range 22–74). 57.1% individuals had previously tested for HIV, median time since last test was 4 years (range <1–15 years). 54.3% individuals had previously tested for HCV, median time since last test was 3 years (range <1–11 years). Median length of time in prison was 3 months (range <1–48 months). 48.6% and 51.4% had never been offered an HIV or HCV test in prison respectively. Only two individuals had tested for HIV and HCV in Prison. 14.3% individuals were already known to be HCV positive. 5.7% (N=2) individuals were newly diagnosed HCV positive but none tested HIV positive. 82.9% felt HIV/HCV testing should be offered in Prison. 71.1% felt this should be done using a mouth swab. 35% had no concerns regarding HIV/HCV testing but in those who did, dislike of needles, receiving a positive result and concerns regarding confidentiality were the commonest barriers to testing.

Conclusions Prevalence of previously undiagnosed HCV was high in this group but HIV prevalence was zero. Uptake of HIV/HCV testing was very low despite good publicity and support from the drug services. This suggests that this method is not a cost effective approach to HIV testing despite oral swabs representing an acceptable mode of testing. Half of attendees had not been offered an HIV or HCV test in prison which needs to be increased. Testing in drug rehabilitation services does not result in high uptake of testing or detection of undiagnosed HIV.