The unlinked anonymous monitoring (UAM) surveys of people who inject drugs (PWID) aim to measure the level of HIV, hepatitis B and hepatitis C in this population. They also monitor the levels of risk and protective behaviours in this population. The surveys provide data on people who inject psychoactive drugs (such as heroin) and also on people who inject image and performance enhancing drugs (IPEDs).

People who inject drugs who are in contact with a sample of specialist drug services (such as needle and syringe programmes and addiction treatment centres) throughout England, Wales and Northern Ireland, are recruited into the surveys. The data is used to assess, develop and evaluate public health interventions.