Diagnosis of Pulmonary Fibrosis

Laboratory Tests. They are used to confirm or rule out the diagnostic suspicion options. The tests performed include a full blood count, and kidney and liver function tests. A study is also made of environmental exposures associated with interstitial diseases, mainly with hypersensitivity pneumonitis. An exhaustive study is made using laboratory tests in case there are autoimmune diseases related to the diagnostic suspicion. 

Simple chest X-ray. It is the first imaging test that is used in the diagnostic approach of patients with a suspicion of interstitial lung diseases. For that reason, a computed tomography (CT) scan of the chest is necessary to determine the type of disease.  

Computed tomography (CT) scan of the chest. It is the main test to diagnose interstitial diseases. The different image patterns can suggest a particular disease, which, added to the clinical and laboratory characteristics can, in some cases, avoid the need to perform a lung biopsy. In the case of idiopathic pulmonary fibrosis, the characteristic radiology pattern is usual interstitial pneumonia (UIP). In the other interstitial diseases, the pattern can vary depending on the disease type. 

Simple spirometry, combined with plethysmography (lung volume measurements), and the carbon monoxide diffusing capacity test. They are of great use in the study of interstitial lung diseases. They confirm the diagnosis when they show restrictive type changes with a low carbon monoxide diffusing capacity. Similarly, they are used to assess the severity of the lung condition and for the follow-up of the patients. 

Six-minute walk test. It allows for the endurance capacity to be assessed in patients with pulmonary fibrosis.  

Fibre Bronchoscopy. In some cases, it is necessary to perform this type of procedure in order to take samples of the lower airway secretions (trachea, the bronchi and bronchioles, and the alveoli) and, occasionally to take biopsy samples.  

Lung biopsy. When the clinical, radiological, and laboratory findings, and the other ancillary tests are unable to reach a consensus diagnosis, it makes it necessary to perform a lung biopsy using video-assisted thoracoscopy. The aim of the test is to obtain specimens of lung tissue so that it may be assessed by the multidisciplinary committee.