Idiopathic pulmonary fibrosis (IPF) can be hard to diagnose because its symptoms are similar to other lung conditions, such as chronic obstructive pulmonary disease (COPD).

A GP can refer you to hospital specialists for a number of tests to help rule out other conditions and confirm the diagnosis.

Your doctor will ask about your medical history and whether there are other factors that could be causing a problem with your lungs, such as whether you:

• smoke or have smoked in the past
• have been exposed to harmful substances at work, such as asbestos
• have other medical conditions

They may also:

• check the sound of your breathing through a stethoscope – a crackling sound can suggest lung scarring (fibrosis)
• look at your fingers to see if the ends are swollen (finger clubbing)
• ask you to walk around for a few minutes to see if you become breathless

Lung function tests (also called pulmonary function tests) assess how well your lungs work and can help indicate what the problem may be.

These tests measure:

• how quickly you can move air in and out of your lungs
• how much air your lungs can hold
• how well your lungs transfer oxygen into your blood and remove carbon dioxide from it (this can be checked using a blood test)

A commonly used lung function test is spirometry. During the test, you breathe into a mouthpiece that's attached to a monitor.

A chest X-ray does not show the lungs in much detail, but can help doctors spot some more obvious problems that could be causing your symptoms, such as cancer or a build-up of fluid.

If IPF is suspected, the chest X-ray will be followed by a CT scan.

A CT scan is similar to an X-ray, but lots more images are taken and these are put together by a computer to create a more detailed image of your lungs.

This can help your doctor spot signs of scarring in your lungs.

If doctors are still not sure what the problem is after these tests, they may suggest having a bronchoscopy.

This is a test where a narrow, flexible tube with a camera (bronchoscope) is passed down into your airways.

Your doctor will look for anything abnormal and may take small tissue samples for testing.

You'll usually be awake during a bronchoscopy and it may cause coughing.

Local anaesthetic will be used to numb your throat so it does not hurt, and you may also be given a sedative injection that will make you feel sleepy during the procedure.

If other tests are not conclusive, a lung biopsy may need to be carried out.

This involves keyhole surgery to remove a small sample of lung tissue so it can be analysed for signs of scarring.

This is performed under a general anaesthetic, where you're asleep. 

Your surgeon makes several small cuts in your side and an endoscope, a thin tube with a camera and a light at the end, is inserted into the area between the lungs and the chest wall.

The surgeon can see the lung tissue through the endoscope and is able to obtain a small sample.