Heart failure (HF) is a clinical syndrome that occurs in patients who because of an inherited or acquired abnormality of cardiac structure and/or function develop a constellation of clinical symptoms (dyspnea and fatigue) and signs (edema and rales) that lead to frequent hospitalizations, a poor quality of life, and a shortened life expectancy.1 Acute dyspnea is a common clinical finding with which the patient is admitted in the emergency department. A rapid and accurate investigation of acute dyspnea is vital since treatment of dyspnea can differ markedly depending on the initial clinical impression. However, the rapid and accurate differentiation of heart failure from other causes of dyspnea remains a clinical challenge. After evaluating patient’s symptoms, conducting a physical examination, and performing electrocardiography (ECG) and chest radiography, the clinician is often left with considerable diagnostic uncertainty, which results in misdiagnosis and delays the initiation of appropriate therapy. Distinguishing between cardiac and non-cardiac causes of dyspnea is often challenging. Therefore, an assay with high sensitivity and high negative predictive value would be useful both in detecting dyspnea due to heart failure and in ruling out the diagnosis in patients with confounding co-morbid conditions. Read more. . .