The probability of this being the most cost effective strategy at the 20,000 per QALY gained threshold is 62%. The deterministic analysis for Verdu found 280pg/ml to be the most cost-effective diagnostic strategy (ICER: 5,952 per QALY gained). The was considered to be due to the fact that this threshold had both the highest sensitivity and highest specificity of all diagnostic strategies. The other scenario analysis conducted using the data from Zaphiriou found that 280pg/ml was the most cost effective threshold (ICER: 15,088 per QALY gained compared to 125pg/ml). The probability of this being the most cost effective strategy at the 20,000 per QALY gained threshold is 19%. In this analysis the 400pg/ml threshold was dominated (more costly, less effective) by 280pg/ml, although the difference in QALYs between these two strategies was very small (0.003). This result was likely to be driven by the high proportion (76%) of HF-REF in the heart failure population for this study, as those with HF-REF receive a greater QALY benefit of being diagnosed and treated than those with HF-PEF. The results of the scenario analyses were much more uncertain than those of the base case. This was considered to be due to the fact that the sensitivity and specificity values of the NT-proBNP across the thresholds are much closer compared to those in the base case diagnostic accuracy study. The committee also considered that the difference in the probabilistic and deterministic results of the Verdu study highlights the uncertainty in the results. From the results of the economic analyses, the committee agreed to recommend that an NT-proBNP level of 400pg/ml be used to refer a patient for echocardiography when heart failure is suspected in a patient presenting with signs and symptoms of heart failure in primary care. 