Pulmonary Embolism Diagnosis

The doctor will ask about your symptoms and medical history, and perform a physical exam. Tests may include:

• Arterial blood gas study -a blood test to identify oxygen levels and other gases that are indicators of lung function
• Chest x-ray -a test that uses radiation to take a picture of structures inside the chest. A pulmonary embolism cannot be seen on the chest x-ray. But, if a part of the lung tissue dies, this can be seen on the x-ray.
• Lung perfusion scan-a test that uses radioactive isotopes to measure breathing and circulation in all areas of the lungs. The presence of an embolus will show as a mismatch between ventilation of the portion of the lung and its blood perfusion.
• CT scan of the chest -a type of x-ray that uses a computer to make pictures of the inside of the chest. A spiral CT is a special type of CT scan that is able to make tri-dimensional pictures. It is also a very fast scan that can be completed in a very short period of time. It has become popular in diagnosing pulmonary embolism.
• Pulmonary angiogram - x-rays taken after a dye is injected into the blood vessels in the lungs. The test shows areas of blockage in the lungs. It provides a clear picture of blood flow through the arteries. But, this test is associated with relatively high risks.
• MR angiography (MRA)-Using this test to diagnose MRA is limited. But, it may be more useful in the future as the technology advances.
• Electrocardiogram (ECG, EKG)-a test that records the heart's activity by measuring electrical currents through the heart muscle. In case of pulmonary embolism, Tachycardia (rapid heart beat) is frequently seen, as well as several rhythm patterns. These results can help in the diagnosis.
• Echocardiography -a test that uses high-frequency sound waves (ultrasound) to examine the size, shape, and motion of the heart. This test may be helpful in a small percentage of patients.
• D-Dimer (a clot dissolving substance) blood test-Increased levels in the blood may suggest the presence of a clot. This test is nonspecific, though. A lot of conditions may cause the level to be elevated.
  • If you have a family history of blood clots and had a few instances of blood clots for no apparent reason, your doctor may order additional blood tests. The tests will look for possible inherited defects in your clotting system. The two most frequent genetic abnormalities that increase your risk of forming blood clots are:
    • Factor V Leiden mutation (seen in up to 40% of cases)
    • Increased factor VIII
• Additional tests-to check blood flow or look for clots in the veins, especially in the legs