Physicians diagnose pulmonary hypertension based on a detailed history and physical examination provided by the patient, as well as the following ancillary tests: 1) Chest X-ray: shows dilated pulmonary arteries and other possible lung diseases; 2) Echocardiography: measures pulmonary artery pressure for screening and to understand structural changes in the heart; 3) Right heart catheterization: accurately measures the hemodynamic parameters of the pulmonary arteries. Special tests needed to determine the type of pulmonary hypertension are: 1) respiratory function; 2) pulmonary vascular CT; 3) nuclear lung perfusion scan; 4) blood sampling for autoantibodies; 5) polysomnography; 6) right heart catheterization.