The committee placed an emphasis on specificity for the very high rule in threshold of 400pg/ml of which this study met the specificity threshold. Very low quality evidence was found for plasma BNP at the threshold of 178pg/ml which reported a poor sensitivity of 47 (33- 62). A further single study of very low quality reported an AUC 0.69. This study did not accurately report the threshold at which this accuracy data was collected. Plasma NT-pro BNP Six studies explored the diagnostic test accuracy of NT-pro BNP for diagnosing chronic heart failure. The quality of the included studies ranged from high to very low. Evidence was downgraded due to risk of bias and imprecision due to the range of the confidence interval around the point estimate. A single study was also downgraded due to indirectness as the study failed to include results for people under 50 years of age as the authors felt as though the prevalence of HF in this group was low. A single high quality study (n=220) reported a high sensitivity of 100 (93-100)% at a number of age specific thresholds (<50 years 50 pg/mL, 50-75 years 75 pg/mL, > 75 years 250 pg/mL). The majority of the evidence for NT-pro BNP was low quality. For women 50 years, a high sensitivity of 100 (90- 100) was observed for a threshold of 67pg/ml which met the sensitivity threshold pre specified by the committee for possible recommendation. For the same group at thresholds of 144pg/ml and 220pg/ml the sensitivities were 94 (80-99) and 91 (76-98) respectively. For men 50 years, high sensitivities of 100 (92-100) and 96 (85-99) were observed at thresholds of 76mg/dl and 93mg/dl respectively. Both of which met the threshold set by the committee. 