Tests and diagnosis

By Mayo Clinic Staff

During the physical exam, your doctor will use a stethoscope to listen carefully to your lungs while you breathe. He or she may also suggest one or more of the following tests.

Imaging tests

  • Chest X-ray. This will usually show the scar tissue typical of pulmonary fibrosis and is useful for following the course of the illness and treatment. Occasionally, the chest X-ray is normal and further tests are required to explain your shortness of breath.
  • Computerized tomography (CT). CT scanners use a computer to combine X-ray images taken from many different angles to produce cross-sectional images of internal structures. A high-resolution CT scan can be particularly helpful in determining the extent of lung damage caused by pulmonary fibrosis. Also, some kinds of fibrosis, like silicosis, have characteristic patterns.
  • Echocardiogram. A sonogram for the heart, an echocardiogram uses sound waves to visualize the heart. It can produce still images of your heart's structures, as well as videos that show how your heart is functioning. This test can evaluate the amount of pressure occurring in the right side of your heart.

Lung function tests

  • Pulmonary function testing. This test requires you to exhale quickly and forcefully through a tube connected to a machine. The machine measures how much air your lungs can hold and how quickly you can move air in and out of your lungs.
  • Oximetry. This simple test uses a small device placed on one of your fingers to measure the oxygen saturation in your blood. Oximetry can serve as an easy way to monitor the course of the disease, sometimes more accurately than a chest X-ray can.
  • Exercise stress test. An exercise test on a treadmill or stationary bike may be used to monitor your lung function when you're active.

Tissue sample (biopsy)

Often, pulmonary fibrosis can be definitively diagnosed only by examining a small amount of lung tissue (biopsy) in a laboratory. The tissue sample may be obtained in one of these ways:

  • Bronchoscopy. In this procedure, your doctor removes very small tissue samples — generally no larger than the head of a pin — using a small, flexible tube (bronchoscope) that's passed through your mouth or nose into your lungs. The risks of bronchoscopy are generally minor — most often a temporary sore throat and hoarseness from the passage of the bronchoscope — but the tissue samples are sometimes too small for an accurate diagnosis.
  • Bronchoalveolar lavage. In this procedure, your doctor injects salt water through a bronchoscope into a section of your lung, and then immediately suctions it out. The solution that's withdrawn contains cells from your air sacs. Although bronchoalveolar lavage samples a larger area of the lung than other procedures do, it may not provide enough information to diagnose pulmonary fibrosis.
  • Surgical biopsy. Although this is a more invasive procedure with potential complications, it's often the only way to obtain a large enough tissue sample to make an accurate diagnosis. During the procedure, surgical instruments and a small camera are inserted through two or three small incisions between your ribs. The camera allows your surgeon to view your lungs on a video monitor while removing tissue samples from your lungs. This is done under general anesthesia.
Mar. 18, 2014