The symptoms of IPF are like those of other, more common lung diseases. Unfortunately, this means the diagnosis is often delayed and misdiagnosis occurs frequently.¹⁰ This can then delay access to specialised care.¹⁵ The delay in diagnosing IPF ranges from six to 18 months.¹⁵ ¹⁶ To avoid this delay, people should be referred to ILD specialised centres.
If you are suspected of having IPF, a multidisciplinary team to confirm diagnosis should include:
- respiratory specialist (i.e. pulmonologists);
- radiologists; and
As a first step, your family doctor should refer you to a respiratory specialist. The respiratory physician may conduct the following diagnostic tests to confirm the diagnosis, or refer you to a centre with expertise in IPF.
Lung auscultation (listening to the lungs)
Lung auscultation is one of the most important investigations as it can diagnose IPF early. ¹⁷ If ‘velcro-like’ crackles can be heard when listening to the patient’s lungs it is a key clinical feature that we can use to recognise IPF.
Pulmonary function testing (PFT)
Pulmonary function tests are also called lung function tests. Spirometry is the most common type of pulmonary function test performed in people with IPF.
During the PFT, you will be asked to breathe in and out in various ways.
These tests can determine how IPF affects the way you breathe and get oxygen. They allow the doctor to measure the total amount of air in your lungs and assess the flow of air in and out of the lungs. This shows how well the lungs are working. ¹⁸ ¹⁹
The test is painless, but requires a lot of effort from you to complete.
Six-minute walk test
This test measures how far you can walk in six minutes, and how much oxygen is present in your body while walking.²⁰ It finds out how fast you run out of oxygen while walking and if you need supplementary oxygen therapy.
Chest X-rays provide a two-dimensional image of your chest using a small amount of radiation. Chest X-rays can often reveal when something is wrong in the lungs. However, they are not good at finding out if you have IPF. If your medical team thinks you may have IPF, they may do an X-ray to look for lung abnormalities that suggest scarring of the lung tissue.¹ However, 5-15% of patients with significant scarring will still have a normal chest X-ray. Therefore, it’s important to remember that IPF cannot be diagnosed from a chest X-ray alone.¹⁰
Blood tests are done to investigate other known causes of interstitial lung diseases (ILD), such as autoimmune diseases*.²¹
High-resolution computed tomography (HRCT)
A High-Resolution Computed Tomography scan⁴, or HRCT scan, is the most important imaging study we use to diagnose IPF.
With a high-resolution CT scan, doctors can create detailed images of the inside of the chest.
The scan is quick, painless, and uses relatively small amounts of X-ray radiation. In half of all cases, a HRCT
Bronchoscopy for trans-bronchial biopsy
During a bronchoscopy, your doctor will insert a bronchoscope (small flexible tube) through your nose or mouth under local or general anaesthesia. The tube is lowered into the lungs through the trachea, or windpipe, and into the lungs.
The doctor then takes a small piece of lung tissue, known as a ‘trans-bronchial biopsy’, for testing. The limited amount of tissue they can take in this test may make it difficult for your doctor to find out for certain what is causing your lung problem.¹⁰
* Autoimmune diseases are diseases where the body produces antibodies that attack its
Bronchoalveolar lavage (BAL)
A BAL involves taking fluid from your lower respiratory tract using a small, flexible tube called a bronchoscope. A sample of cells is then taken from this fluid for testing. This is a minimally invasive procedure that can be very helpful to exclude or investigate other interstitial lung disease. However, there are risks associated with a bronchoscopy, which your doctor will discuss with you.
A lung biopsy is a surgical procedure in which a small piece of lung tissue is removed and analysed. You will only need a lung biopsy if doctors cannot diagnose IPF from:
- your medical history;
- a physical examination;
- blood tests; and
- a high-resolution CT scan.
A lung biopsy is used together with a high-resolution computed tomography (HRCT), to assess how the disease is progressing.¹⁰ Depending on your individual risk factor as well as on the preference of the surgeon, lung biopsies can be performed as:
- so-called ‘open surgery’; or
- video-assisted thoracoscopic surgery (VATS).
VATS is less invasive than open surgery, but not all patients are suitable for lung biopsy.
Genetic counselling could be useful for patients with a family history of lung fibrosis.
How doctors diagnose idiopathic pulmonary fibrosis (IPF)
When doctors suspect you have pulmonary fibrosis, they must try different things to confirm the diagnosis and find the cause. If your doctor suspects you have idiopathic pulmonary fibrosis (IPF), you should be carefully evaluated to exclude any other interstitial lung disease (ILD).
If the medical team cannot find the cause of your ILD, an HRCT scan that shows ‘usual interstitial pneumonia’ (UIP) means you have IPF. If the HRCT scan shows you do not have UIP, doctors can diagnose IPF using specific HRCT scans and by identifying changes in lung tissue.
Diagnosis of IPF is most accurate when it is made through multidisciplinary discussion among ILD experts. Multidisciplinary discussion is when different medical experts work together. See explanation of multidisciplinary teams in the next section.