Evidence statements summarising the results of the analysis can be found below. The full analysis can be found in Appendix O. A cost-utility analysis was undertaken to determine the most cost effective threshold level of natriuretic peptide for referral from primary care for echocardiography and specialist clinical assessment. A decision tree with an attached Markov model was used to estimate lifetime quality- adjusted life years (QALYs) and costs from a current UK NHS and personal social services perspective. The analysis was conducted in accordance with the NICE reference case unless otherwise stated including discounting at 3.5% for costs and QALYs. The population entering the model are those presenting to primary care with signs and symptoms of heart failure, including breathlessness, fatigue or ankle swelling and upon clinical examination the general practitioner (GP) suspects that the patient has heart failure. The NICE 2010 Chronic Heart Failure guideline (CG108) recommendations state that patients with a previous history of myocardial infarction (MI) should be referred for echocardiography without a natriuretic peptide test. However, the committee decided that this was no longer appropriate as the definition of MI has changed over time and now includes many scenarios that differ from what was included in the Mant et al. 2009 HTA which formed the basis of the recommendation in the 2010 guideline212 . People who first Chronic Heart Failure Diagnosing heart failure present to an acute emergency setting were excluded as this population is covered by the Acute Heart Failure guideline (CG187). The committee decided to exclude BNP testing from this analysis for the multiple reasons. The most important factor is that the clinical review demonstrates that NT-proBNP has a greater sensitivity over a range of thresholds compared to BNP. 