Pulmonary embolism

Diagnosing pulmonary embolism

It can be hard for doctors to decide if you have a pulmonary embolism because the symptoms are similar to many other conditions.

It’s important to diagnose it accurately because treating a pulmonary embolism isn’t always easy and treatments can cause side effects.

If your doctor suspects a pulmonary embolism, you’ll have a number of tests, such as a chest X-ray or an ultrasound scan to see if you have a blood clot in your leg, and tests to check how well your lungs are working.

You may also have more specialised tests such as:

  • a blood test to look for a protein called D-dimer. High levels of D-dimer in your blood suggest that pieces of blood clot are loose in your bloodstream.
  • computerised tomography pulmonary angiography (CTPA) to see the blood vessels in your lungs. You are injected with a dye that helps to show your blood vessels and a scanner uses X-rays to build a detailed picture of the blood flow in your lungs.
  • ventilation-perfusion scan, also called a V/Q scan, to examine the flow of air and blood in your lungs. You will be asked to inhale a slightly radioactive gas and given an injection of slightly radioactive material. If the scan shows parts of your lungs have air in them but no blood supply, this may be the result of a pulmonary embolism.

Next: Treatment for pulmonary embolism >

Download our pulmonary embolism PDF (266KB)

Last medically reviewed: March 2015. Due for review: March 2018

This information uses the best available medical evidence and was produced with the support of people living with lung conditions. Find out how we produce our information. If you’d like to see our references get in touch.