question: How to diagnose Pulmonary Hypertension?: Your doctor will diagnose pulmonary hypertension (PH) based on your medical and family histories, a physical exam, and the results from tests and procedures.  PH can develop slowly. In fact, you may have it for years and not know it. This is because the condition has no early signs or symptoms.  When symptoms do occur, they're often like those of other heart and lung conditions, such as asthma. This makes PH hard to diagnose.  Medical and Family Histories  Your doctor may ask about your signs and symptoms and how and when they began. He or she also may ask whether you have other medical conditions that can cause PH.  Your doctor will want to know whether you have any family members who have or have had PH. People who have a family history of PH are at higher risk for the condition.  Physical Exam  During the physical exam, your doctor will listen to your heart and lungs with a stethoscope. He or she also will check your ankles and legs for swelling and your lips and skin for a bluish color. These are signs of PH.  Diagnostic Tests and Procedures  Your doctor may recommend tests and procedures to confirm a diagnosis of PH and to look for its underlying cause. Your doctor also will use test results to find out the severity of your PH.  Tests and Procedures To Confirm a Diagnosis  Echocardiography. Echocardiography (EK-o-kar-de-OG-ra-fee), or echo, uses sound waves to create a moving picture of your heart. This test can estimate the pressure in your pulmonary arteries. Echo also can show the size and thickness of your right ventricle and how well it's working.  Chest x ray. A chest x ray takes pictures of the structures in your chest, such as your heart, lungs, and blood vessels. This test can show whether your pulmonary arteries and right ventricle are enlarged.  The pulmonary arteries and right ventricle may get larger if the right ventricle has to work hard to pump blood through the pulmonary arteries.  A chest x ray also may show signs of an underlying lung disease that's causing or contributing to PH.  EKG (electrocardiogram). An EKG is a simple, painless test that records the heart's electrical activity. This test also shows whether your heart's rhythm is steady or irregular. An EKG may show whether your right ventricle is enlarged or strained.  Right heart catheterization. This procedure measures the pressure in your pulmonary arteries. It also shows how well your heart is pumping blood to the rest of your body. Right heart catheterization (KATH-e-ter-ih-ZA-shun) can find any leaks between the left and right side of the heart.  During this procedure, a thin, flexible tube called a catheter is put into a blood vessel in your groin (upper thigh) or neck. The tube is threaded into the right side of your heart and into the pulmonary arteries. Through the tube, your doctor can do tests and treatments on your heart.  Tests To Look for the Underlying Cause of Pulmonary Hypertension  PH has many causes, so many tests may need to be done to find its underlying cause.  Chest CT scan. A chest computed tomography (to-MOG-ra-fee) scan, or chest CT scan, creates pictures of the structures inside your chest, such as your heart, lungs, and blood vessels. These pictures can show signs of PH or a condition that may be causing PH.  Chest MRI. Chest magnetic resonance imaging, or chest MRI, shows how your right ventricle is working. The test also shows blood flow in your lungs. Chest MRI also can help detect signs of PH or an underlying condition causing PH.  Lung function tests. Lung function tests measure how much air you can breathe in and out, how fast you can breathe air out, and how well your lungs deliver oxygen to your blood. These tests can help detect a lung disease that may be causing PH.  Polysomnogram (PSG). This test records brain activity, eye movements, heart rate, and blood pressure while you sleep. A PSG also measures the level of oxygen in your blood. A low oxygen level during sleep is common in PH, and it can make the condition worse.  A PSG usually is done while you stay overnight at a sleep center. For more information about this test, go to the Diseases and Conditions Index Sleep Studies article.  Lung ventilation/perfusion (VQ) scan. A lung VQ scan measures air and blood flow in your lungs. This test can help detect blood clots in your lung's blood vessels.  Blood tests. Blood tests are used to rule out other diseases, such as HIV, liver disease, and autoimmune diseases (such as rheumatoid arthritis).  Finding Out the Severity of Pulmonary Hypertension  Exercise testing is used to find out the severity of PH. This testing consists of either a 6-minute walk test or a cardiopulmonary exercise test.  A 6-minute walk test measures the distance you can quickly walk in 6 minutes. A cardiopulmonary exercise test measures how well your lungs and heart work while you exercise on a treadmill or bicycle.  During exercise testing, your doctor will rate your activity level. Your level is linked to the severity of your PH. The rating system ranges from class 1 to class 4.  Class 1 has no limits. You can do regular physical activities, such as walking or climbing stairs. These activities don't cause PH symptoms, such as tiredness, shortness of breath, or chest pain.  Class 2 has slight or mild limits. You're comfortable while resting, but regular physical activity causes PH symptoms.  Class 3 has marked or noticeable limits. You're comfortable while resting. However, walking even one or two blocks or climbing one flight of stairs can cause PH symptoms.  Class 4 has severe limits. You're not able to do any physical activity without discomfort. You also may have PH symptoms while at rest.  Over time, you may need more exercise tests to find out how well your treatments are working. Each time testing is done, your doctor will compare your activity level with the previous one.