The present invention relates to a method for differentiating in a subject suffering from chronic shortness of breath (dyspnea) between (i) a pulmonary disease, (ii) a cardiovascular complication, (iii) a cardiovascular complication accompanied by a pulmonary disease and (iv) dyspnea without cardiovascular or pulmonary causes. The method comprises the steps of determining an amount of a pulmonary surfactant protein in a sample of a subject, determining an amount of a natriuretic peptide in a sample of said subject, and differentiating between (i) a pulmonary disease, (ii) a cardiovascular complication, (iii) a cardiovascular complication accompanied by a pulmonary disease and (iv) chronic dyspnea without cardiovascular or pulmonary causes by comparing the amount determined in a) and the amount determined in b) with a reference amount for each. The present invention further provides a device and a kit for carrying out the inventive methods.