Bilardi et al. BMC Public Health 2010, 10:70 http://www.biomedcentral.com/1471-2458/10/70 sexually active young people under the age of 25 years. Australian data show that diagnosis rates are highest among young women aged under 25 years, who accounted for just over 40% of all chlamydia notifica- tions in 2008 [1]. Given that almost 90% of women in this age group consult a general practitioner (GP) at least once a year [5], general practice is considered an ideal site through which to offer chlamydia testing. Currently in Australia only 12% of women in this age group are tested for chlamydia each year [6]. Mathematical modelling has suggested that testing needs to increase to approxi- mately 30% annually among men and women in this age group to achieve a significant reduction in prevalence among women [7]. Previous randomised controlled trials (RCT) have used a variety of interventions to increase chlamydia testing in general practice, including educational or continuing med- ical education interventions [8,9], computerised reminders [10] and concurrent pap smear and chlamydia testing [11], however all have had limited success in increasing testing. In practice, a number of barriers to increased testing exist for GPs including: a lack of time, insufficient knowledge about the benefits of testing, discomfort raising the issue of sexual health in unrelated consultations and difficulty remembering to offer testing to patients [12-15]. Financial incentives have been used for many years internationally to improve quality of care in general practice [16-18]. In the UK, as part of the pilot chlamy- dia testing program, opportunistic chlamydia testing for young women increased when general practices were offered financial incentives for testing [19]. In Australia, the use of GP financial incentives was first introduced in 1998 in the form of the General Practice Immunisa- tion Incentive Scheme (GPII) and successfully increased childhood immunisation to target rates [5]. The use of GP financial incentives to increase chlamydia testing in Australian general practice has been recommended by a number of researchers in the field [5,10,12,15], however to date has not been examined. The aim of this pilot study was to use a RCT design to determine if offering a $AUD5 payment per chlamy- dia test to GPs would increase chlamydia testing among 16 to 24 year old women attending general practice. Methods Setting A cluster RCT was undertaken in general practice clinics in the State of Victoria (population 5.4 million) [20], Australia, between May 2008 and January 2009. Page 2 of 9 equivalent GPs willing to participate and collectively saw a minimum of 250 women aged 16 to 24 years in the 12 months prior to the trial. Recruitment methods General practices were selected from a database collated from the Victorian ‘Yellow Pages’ telephone directory. In order to provide adequate representation of general practices across the state, practices were recruited by geographical location using the Accessibility Remoteness Index of Australia (ARIA) [21] and socio-economic sta- tus using the Socio-Economic Indexes for Areas (SEIFA) [22]. A total of eight practices were recruited in metro- politan areas (highly accessible) - two in each SEIFA quartile - and four in regional/rural areas (accessible/ moderately accessible). Practices were initially telephoned by a research assis- tant to invite participation and provide further informa- tion to interested and eligible clinics. Interested practices were visited by a research assistant to further outline the study and obtain consent from GPs. GPs consented to the collection of de-identified chlamydia testing data and consultation data on female patients 16 to 24 years old. A total of 145 practices were approached to recruit 12 prac- tices into the study. Reasons for non-participation included a lack of response from GPs (57%), no interest from GPs (33%), a lack of time (4%), interest shown after recruitment period had ceased (4%) and clinic participa- tion in other studies (2%). Randomisation The unit of randomisation was the general practice. The eight metropolitan practices were paired within the four SEIFA quartiles and one practice in each quartile was randomised to receive the intervention protocol and the other the control protocol, using a pre-determined ran- domisation sequence prepared by the trial statistician. The statistician was contacted to make the randomised assignment once two practices had been recruited for any particular SEIFA quartile. The four regional/rural practices were also paired - two rural and two regional - and were assigned within pairs to intervention and con- trol in the same way as the metropolitan practices. The allocation was not revealed to staff at either of the paired practices until representatives from both had completed the pre-trial requirements (questionnaire, audit, education session). GPs in the practice were then contacted by letter to inform them of the allocation relevant to their practice and reminded of testing pay- ment or non-payment. Eligibility General practices were eligible to participate if they were located within Victoria, had a minimum of two full time Intervention and control GPs in both the intervention and control groups were required to complete a pre-trial questionnaire, a clinical