Pulmonary arterial hypertension (PAH) disguises itself as several heart and lung conditions. PAH causes many of the same symptoms as heart disease and asthma, for example. Distinguishing between those conditions and PAH can be difficult, but several tests and tools can help your doctor decide if your symptoms are the result of the rare lung condition or some other cause.

What Is Pulmonary Arterial Hypertension?

Pulmonary arterial hypertension (PAH) is high blood pressure in the arteries of the lungs and the heart. The pulmonary arteries and capillaries carry blood from the heart to the lungs where the blood drops off oxygen-depleted cells and picks up oxygen-rich cells. Any narrowing or blockages in the pulmonary arteries can cause increased blood pressure. This type of high blood pressure is known as PAH. Over time, the increased pressure weakens the right side of the heart and the pulmonary arteries. This can ultimately lead to heart failure and possibly death.

Pulmonary Arterial Hypertension Is Hard to Catch

PAH isn’t easily caught on a routine physical exam. It’s hard to find and diagnose, even when doctors are looking for it. The symptoms of PAH disguise themselves as symptoms of other similar conditions. Even as PAH progresses and becomes worse, doctors may have a difficult time distinguishing between PAH and other heart and lung conditions. To decide what is causing your symptoms, your doctor may use one or more tests.

Find out how doctors diagnose pulmonary arterial hypertension »

Tests Used to Diagnose PAH

Below are some of the tests that your doctor may use to detect the presence of PAH.

Blood Test

A blood test can help doctors see what is in your blood. They may be able to identify substances related to PAH. They may also be able to rule out other conditions or diseases with this test.

Chest X-Ray

If PAH is advanced, a chest X-ray may show doctors the enlarged portion of your heart. However, this imaging test is not always successful. A chest X-ray will appear normal for one third of people who have PAH, according to the Mayo Clinic.


This test measures the electrical functions as they happen in your heart. Electrical functions are responsible for making your heartbeat regularly, in rhythm, and without error. A slight change in the electrical impulses can have big consequences for your heart and body.


PAH can usually be found with an echocardiogram. An echocardiogram is a noninvasive procedure that uses sound waves to give doctors a picture of your heart without performing open heart surgery. With this test, doctors can see if any part of the heart isn’t beating properly, or if one part has grown enlarged.

Two types of echocardiogram are used. The first is called a Doppler echocardiogram. This procedure involves placing a receiving device on your chest. The second is called a transesophageal echocardiogram. It requires doctors to place an imagine device into your esophagus. 

An echocardiogram is used to check for and diagnose several cardiac conditions, including PAH. Having this test may help your doctor rule out other conditions, even if he or she can’t confirm a PAH diagnosis.

Heart Catheterization

If an echocardiogram is not conclusive or definitive, your doctor may request that you have a right heart catheterization. This test allows doctors to measure the pressure in your arteries and heart with a small, flexible tube that is inserted through the neck or groin.

Pulmonary Function Test

This test allows doctors to see how much air your lungs can hold. During the procedure, your doctor will also take a measurement of how the air flows into and out of your lungs. This test may be done several times so doctors can check for changes in your lungs’ capabilities.

CT Scan

A computed tomography (CT) scan allows doctors to see into your organs on a layer-by-layer level. This allows them to check for artery narrowing, blockages, or damage.


Magnetic resonance imaging (MRI) tests can give your doctors a picture of your body’s blood vessels. Like a CT scan, an MRI allows doctors to have a layer-by-layer look at all the organs involved.

Diagnosing Risk Factors and Related Conditions

People with a family history of PAH are at an increased risk for developing PAH, too. Your doctor may conduct a gene screening to see if you have the gene connected to PAH.

According to the American Journal of Cardiology, part of diagnosing PAH should involve identify a person’s individual risk factors for PAH. It should also involve looking for any conditions that might contribute to PAH or make the disease worse. For example, people with heart disease and congenital heart defects are at an increased risk for developing PAH. Also, people with scleroderma and HIV are more likely to have PAH. Finding a risk factor for PAH makes a PAH diagnosis easier and potentially faster.