lung and airway disorders
Hypersensitivity Pneumonitis
Diagnosis of Hypersensitivity Pneumonitis
Chest computed tomography The diagnosis of hypersensitivity pneumonitis is based partly on symptoms, the clinical features, identification (if possible) of the dust or other substance causing the problem, as determined by what the person says, an analysis of the workplace by industrial hygiene specialists, , or a combination. Doctors may suspect the diagnosis based on chest x-ray findings. Usually, however, computed tomography (CT) of the chest is needed to help confirm the diagnosis. Results of Pulmonary Function Testing (PFT) —which measure the lungs' capacity to hold air and their ability to move air in and out and to exchange oxygen and carbon dioxide—are used to assess how well the lungs work and may help support a diagnosis of hypersensitivity pneumonitis. In cases that are not clear, especially when an infection is suspected, doctors may remove small pieces of lung tissue for examination under a microscope (lung biopsies). To obtain a tissue sample, a viewing tube may need to be inserted through the chest wall ( Thoracoscopy ) and also used to examine the lung surface and pleural space, or an operation in which the chest wall is opened ( Occasionally, blood tests are needed to look for clues to the substance causing the hypersensitivity or to eliminate other possible causes. 