A duplex ultrasound is the most common test used to make a deep vein thrombosis diagnosis. This test uses sound waves to evaluate the flow of blood in your veins. This test involves the following steps:

 

• A gel is put on the skin of the leg
• A handheld device is placed on the leg and passed back and forth over the affected area
• This device sends sound waves from the leg to an ultrasound machine
• A computer then turns the sounds into a picture
• The picture is displayed on a TV screen where your doctor can see the blood flow in your leg.

 

This is an indirect way to diagnose a source of pulmonary embolism.

 

Blood work is used to check for inherited disorders that cause clots. Blood work is also used to measure the amount of oxygen and carbon dioxide in the blood (arterial blood gas), because pulmonary embolism may change the levels of oxygen and carbon dioxide in the blood.

 

Diagnosing Pulmonary Embolism: Additional Tests

Additional tests used in diagnosing pulmonary embolism include:

 

• Ventilation/perfusion lung scan (V/Q scan)
• Pulmonary angiography
• Spiral computed tomography (CT) scan
• Magnetic resonance imaging (MRI)
• Echocardiogram
• D-dimer.

 

A V/Q scan is a test that uses a radioactive material to see how well air and blood are flowing to all areas of the lung.

 

A pulmonary angiography is an accurate, invasive test that is used to diagnose pulmonary embolism. A trained specialist will thread a flexible tube called a catheter through the groin or arm to the blood vessels in the lung. The specialist will then inject a dye to take a picture of the blood flow through the blood vessels in the lungs. This test is not available at all hospitals, and a trained specialist is required to perform this test.