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. The committee considered the base case analysis to be robust to changes in model assumptions and data inputs. However, they acknowledged the uncertainty that remains for this question due to the inconsistencies in the study populations and diagnostic accuracy data across the studies assessed in the model. However, the results of the scenario analyses using different diagnostic accuracy data from alternative studies were highly uncertain. Therefore, overall the committee agreed that there was currently not enough evidence to support reducing the threshold from 400pg/ml as recommended in the previous guideline. Suspected heart failure and CKD or AF No previously published economic evaluations were identified in these populations. Due to a lack of diagnostic accuracy data for the AF and CKD patients these cohorts were not included in the original economic analysis. However, as mentioned above the committee did not consider there to be a strong rationale to have a different test threshold for people with CKD and suspected heart failure. Chronic Heart Failure Diagnosing heart failure NICE 2018. All rights reserved. Subject to Notice of rights. ISBN: 978-1-4731-3093-7 Other considerations General suspected heart failure population The 2010 guideline considered a wider breadth of evidence than was considered in this review. This review protocol was limited to studies of patients presenting in a primary care or outpatient setting, on the basis that studies of patients in an acute setting now fall within the remit of the acute heart failure guideline. 