Respondent-driven sampling in a syringe exchange setting.
Aims: Respondent-driven sampling is a research technique, new to the Scandinavian setting, used in hard-to-reach populations, such as subjects at risk for HIV, including drug users. This study aimed to evaluate the use of respondent-driven sampling originating from syringe exchange clients, as a method to identify 'hidden' drug users without treatment or social service contact. Methods: Nine heroi