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This information was reviewed and approved by Joshua J. Solomon, MD, Katherine Rosen, RN, MSN, ANP-C (1/31/2022).

When the diagnosis of ILD is suspected, your doctor considers the following:

  • Your medical history — This includes:

    • a review of all the person’s symptoms

    • a listing of current and former medications

    • a review of any environmental and occupational exposures to dust, gases, chemicals, pets (in particular birds) and humidifiers.

  • A complete physical examination — Findings of crackling sounds in the lungs and changes in the skin, joints and fingernails can help direct further evaluation.

  • A chest X-ray and high resolution computed tomography (CT) scan — Results are often abnormal with ILD. Chest x-rays and routine CT scans of the chest alone are not adequate for evaluating or diagnosing ILD.

  • Pulmonary function tests —These breathing test results help determine the severity of ILD.

  • Arterial blood gas — The arterial blood gas test measures the amount of oxygen and carbon dioxide in your blood. The results may be normal or show a reduced oxygen level.

  • Exercise testingExercise tests may show a decrease in your oxygen level during activity. Testing may include a six–minute walk, oxygen titration and exercise tolerance test.

  • Laboratory data — Blood work may be done to test for autoimmune disease and other disorders that can cause ILD.

  • Bronchoscopy with bronchoalveolar lavage — A bronchoscopy may be done to check for inflammatory cells in your lungs or to sample small pieces of the lung to look for evidence of a specific ILD. Bronchoscopy involves inserting a tube through the nose or mouth into your trachea (windpipe) to see the airways. In bronchoalveolar lavage a small amount of sterile saline or salt water is placed in one area of your lung and then withdrawn. This fluid contains cells that will be analyzed under the microscope. Small biopsy tools may be used through the bronchoscope if indicated.

  • Surgical lung biopsy — In many cases of ILD, a surgical lung biopsy is needed to get enough lung tissue to make a specific diagnosis. This may be performed with the use of a thoracoscope. This allows the surgeon to biopsy multiple areas of one lung through a few very small incisions.


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