Does cost feedback modify demand for common blood tests in secondary care? A prospective controlled intervention study.

Background: Behavioural insights or 'nudge' theory suggests that non-directional interventions may be used to modify human behaviour. We have tested the hypothesis that the provision of the cost of common blood tests with their results may modify subsequent demand for blood assays.

Methods: The study design was a prospective controlled intervention study. The individual and annual institutional cost of full blood count (FBC), urea and electrolytes (U&E) and liver function test (LFT) blood assays were added to the electronic results system for inpatients at the intervention teaching hospital, but not the control hospital.

Results: In the 12 months after the intervention was implemented, demand for FBC dropped by 3% (95% confidence interval (CI) 1-5; p<0.001), U&E by 2% (95% CI 0-4; p=0.054) and there was no change in demand for LFT compared to the control institution.

Conclusions: Providing cost feedback to clinicians for commonly used blood tests is a viable intervention that is associated with small reductions in demand for some, but not all blood assays. As this is an easily scalable approach, this has potential to enable efficient healthcare delivery, while also minimising the morbidity experienced by the patient.