General suspected heart failure population Eight diagnostic accuracy studies were included that evaluated the diagnostic accuracy of NT-proBNP and/or BNP at diagnosing heart failure in the general suspected heart failure population. The quality of the evidence ranged from high to very low. Common issues in in the studies were risk of bias due to unclear participant selection methods, high (or not reported) loss to follow up, extended length of time between BNP test and echo, and poor reporting of accuracy results. Some studies were also downgraded for indirectness of the population, where the prevalence of heart failure was much higher than would be expected in the target population indicating the populations may have been from different settings with a potential variation in the distribution of symptoms and severity. Various test thresholds were reported in the included studies. As the committee was interested in the relative accuracy of the tests at different thresholds, it was only appropriate to meta-analyse sensitivity and specificity data where multiple studies used the same test (NT-proBNP or BNP) and reported data at the same test threshold. While it was not possible to assess statistical heterogeneity for data that was not meta-analysed, upon viewing the forest plots, the committee agreed that there was clearly a high degree of inconsistency in the results across the thresholds. That is, the expected relationship between sensitivity and specificity and the test threshold was not clearly apparent. This suggested that the study populations or other features of the study design or quality were contributing to differences between test accuracy at different thresholds, rather than these differences necessarily reflecting true threshold-related differences in test accuracy. 