ISBN: 978-1-4731-3093-7 potentially biasing the overall results of the model. The committee acknowledged that in practice the level of NT-proBNP is often used as part of the criteria for diagnosing heart failure but agreed that for our purposes in truly identifying the diagnostic accuracy of the test, this data was not considered to be suitable. Secondly, the committee also noted that this analysis did not report any assumptions, costs or QALYs applied to the non-heart failure population in the model. The committee inferred from the results of the model that this population was not directly accounted for, and supposed that the model assumed there was no effect on this population of a differential diagnosis if they enter the diagnostic pathway for heart failure. Thirdly, the committee stated that the definition of MI has changed over time and now includes many scenarios that differ from what was originally meant in the 2010 guideline, and as a result having a history of myocardial infarction (MI) should no longer be a criterion for early echocardiography. Therefore the NICE 2010 guideline diagnostic pathway was no longer considered to be an appropriate strategy to assess. Due to the high clinical and economic importance of this question, an original cost-effectiveness analysis was therefore conducted for this question. The model sought to determine which NT-proBNP threshold is the most cost effective for diagnosing heart failure in patients presenting with signs and symptoms of heart failure. The comparators included were NT-proBNP thresholds of 400pg/ml, 280pg/ml and 125pg/ml, and echocardiography for all. Due to the inconsistency in the pooled results and the very low quality of this data as discussed above, the committee did not consider it appropriate to use the pooled results of these thresholds for the base-case analysis. 