GPs order blood tests for diagnosis, ongoing monitoring of health conditions, and screening, regularly as a core part of their work. However, there is wide variation in testing rates amongst doctors and in the proportion of tests that yield abnormal results. This team is creating an easily accessible tool to show testing rates for individual GP practices, comparing them to population trends, and alerting GPs to important changes. Modelled on the successful OpenPrescribing.net tool, they will produce simple actionable data for clinicians, such as statistical process control techniques to give early warning of drifting practice, giving them targeted opportunities to improve patient care and get better value for the NHS.