Acute dyspnea is a common clinical finding with which the patient is admitted in the emergency. Heart failure carries a serious prognosis comparable to many malignancies. In developing countries, 2-3% of the population suffers from heart failure and is the most frequent cause of hospitalization among people older than 65 years of age.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. Therefore, an assay with high sensitivity and specificity would be useful both in detecting dyspnea due to heart failure and in ruling out the diagnosis in patients with confounding co-morbid conditions. A definitive CHF diagnosis is often based on right heart catheterization by means of echocardiography. Lack of immediate availability and high cost make these studies prohibitive as emergency department screening tests. Therefore, a blood test that could rapidly and accurately confirm or exclude the diagnosis of CHF in the urgent care setting would be a valuable clinical tool.