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    Pulmonary Function Testing

    Pulmonary function tests are a group of procedures that measure the function of the lungs, revealing problems in the way a patient breathes. The tests can determine the cause of shortness of breath, and may help confirm lung disease such as asthma, bronchitis, or emphysema. Some tests may be repeated after you inhale medicine that temporarily enlarges your airways to see if there is a positive change in breathing.

    Pulmonary function labs are located on two campuses:
    St. Luke's
    3555 Cesar Chavez
    4th floor, Room 401
    San Francisco, CA
    Convenient scheduling
    (415) 641-6565

    2351 Clay Street, 5th Floor
    San Francisco, CA
    Directions to the pulmonary function lab on our Pacific Campus

    Common Tests

    There are several tests that may be performed but the most common are spirometry, gas diffusion, and plethysmography. Here are basic definitions to help explain the most common tests.

    Spirometry – this test is usually done first. It measures how quickly your lungs can move air in and out and how much air they can move in and out.

    Gas diffusion – this test measures the amount of oxygen and other gases that cross the lung air sacs per minute. These tests evaluate how well gases are being absorbed into your blood from your lungs. For this test a small finger prick is done to collect a few samples of blood to help calculate the test. Blood collection is usually not done for children.

    Plethysmography – airway resistance can be directly measured, which determines the pressure required to produce a given flow. For this test, you sit in a “booth” and breathe through a mouthpiece while pressure and airflow measurements are collected.

    Exercise testing – This test evaluates the effect of exercise on the lung function. If you are scheduled for this test, we recommend that you wear comfortable clothing or bring a change of clothes such as sweat pants or shorts. Walking or jogging shoes will also be needed.

    Arterial Blood Gases (ABG) – ABG’s can show how well your lungs are getting oxygen into your blood. For this test a sample of blood is drawn from your artery, usually drawn from the wrist area.

    Please print and complete this pulmonary diagnostic services questionnaire (PDF, 24KB) and bring it with you the day of your scheduled test.

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    About Our Pulmonary Diagnostic Laboratories

    The respiratory therapists in the pulmonary diagnostic labs at CPMC and St. Luke’s have well over 100 years of experience practicing respiratory care. They have worked in all areas of respiratory care, including emergency room and trauma, transplant, newborn, pediatric, and adult ICU’s, and education.

    The current team includes respiratory therapists who have worked extensively with the Cystic Fibrosis population since 1989, with both adult and pediatric populations. Our patients at CPMC range in age from 6 to 106, as well as even some infants for certain specialized tests. The pulmonary labs are also able to provide care to patients who speak almost every language using our professional interpretation services.

    The pulmonary diagnostic labs at CPMC and St Luke’s are held to the high standards of care defined by the clinical guidelines of the American Thoracic Society for pulmonary function testing. The pulmonary lab is a high quality, high volume operation that routinely performs diagnostic procedures often not available at many other hospitals.

    All respiratory therapists at CPMC are licensed by the state of California to practice respiratory care. Whether the procedures are basic pulmonary function testing to airway reactivity challenges, simple exercise testing to complex cardiopulmonary exercise stress testing, or bronchoscopy, each therapist has the education, credentialing, training and experience to provide the best care that you should expect.