PH can be difficult to diagnose because it shares many of its symptoms with other more common conditions and requires specialized tests to be confirmed. When doctors suspect PH, they may order a series of preliminary tests to rule out other conditions before referring a patient to a specialist. These tests include an echocardiogram, blood tests, chest X-rays, an electrocardiogram, and pulmonary function tests. A specialist can confirm a PH diagnosis after conducting one or more of these tests: exercise tolerance tests, CT scanning/imaging, ventilation/perfusion lung scan, and right heart catheterization.