Bronchitis Diagnosis

Reaching a medical diagnosis of chronic bronchitis is a process of elimination. Other possible lung diseases must be ruled out to arrive at a diagnosis of bronchitis. In most cases of chronic bronchitis, symptoms of emphysema are also discovered during the medical diagnosis. When both diseases co-exist, the condition is referred to as COPD (chronic obstructive pulmonary disease).

Medical History: Listing Symptoms

Obstructive Lung DiseasesGathering a medical history of symptoms is the first step in a chronic bronchitis diagnosis. Characteristic symptoms of chronic bronchitis include a wet cough that produces mucus, shortness of breath, wheezing, and frequent throat clearing.

How long symptoms have been experienced is especially important. A medical diagnosis of chronic bronchitis can only be made if coughing and other symptoms have been present for at least three months out of the year for two years in a row.

Physical Exam: How Well Do Your Lungs Function

During the physical exam, the doctor will use a stethoscope to listen to lung sounds. The physical exam may reveal sounds of wheezing, a whistling sound in the lungs. Wheezing is due to inflamed airways and the accumulation of mucus in the bronchial tubes. If the physical exam reveals abnormal lung sounds consistent with a medical diagnosis of chronic bronchitis, a spirometry test may be ordered.

Spirometry Testing

Spirometry measures lung function. During a spirometry test your breathing is monitored as you breathe into a tube attached to a spirometer. The spirometry machine measures lung volume, and how easily air travels through the lungs. This provides information necessary to make a medical diagnosis. If the spirometry results and the physical exam suggest a need, further testing may be ordered.

Additional Testing: Chest X-Rays and Mucus Analysis

Sputum tests: A sputum test requires a sample of mucus. The mucus is analyzed for signs of infection that may be responsible for symptoms. Excess mucus is an inviting breeding ground for bacteria.

Exercise testing: This provides additional information about lung function.

Pulmonary Function Tests:In addition to spirometry, pulmonary function tests measure how effectively the lungs can ventilate gases. For example, to illustrate how effectively gases are passing from the lungs to the bloodstream the carbon monoxide-diffusing capacity can be measured. Chronic bronchitis sufferers often have a decreased diffusing capacity.

Blood gas readings: Severe symptoms may require blood gas readings to determine the amount of oxygen and carbon dioxide in the bloodstream. Low levels of oxygen require treatment with an oxygen mask.

Chest x-rays: Chest x-rays are used during a medical diagnosis to rule out other possible symptom causes, including pneumonia and lung cancer.


American Lung Association. (2002). Chronic bronchitis. Retrieved November 23, 2003, from

Beers, M. H.