Pulmonary Function Laboratory

Appointments: (844) 795-4968

The Pulmonary Function Lab at Robert Wood Johnson University Hospital (RWJUH) administers pulmonary function tests (PFTs) for adults and children.

If you are having trouble breathing, your physician may prescribe one or more PFTs to determine how well air moves through your lungs and whether the lungs are oxygenating the blood well.

Results of these tests can help doctors diagnose lung diseases or conditions including asthma, chronic obstructive pulmonary disease (COPD), cystic fibrosis, vocal cord dysfunction (VCD) and shortness of breath or chronic cough caused by occupational or environmental exposure.

PFTs can also help determine whether you will be able to tolerate certain surgeries and medical procedures.

All patients must be referred by a physician. A prescription is required prior to making an appointment and must be presented when arriving at the laboratory for testing.

High Standards and Expert Service

The Pulmonary Function Lab is staffed by registered respiratory therapists who are also credentialed as certified or registered pulmonary function technologists (CPFT/RPFT). Their expert knowledge will ensure accurate testing and results. Our lab’s membership in the American Thoracic Society Pulmonary Laboratory Registry means we maintain rigorous quality control standards in patient testing, as well as diagnostic machine calibration and maintenance.

Services We Provide


Spirometry Test

This test measures how much air you can take into your lungs and how efficiently air flows out of the lungs during a forceful exhalation. You blow hard into a special computer-controlled meter, and it displays the measurement.

Diffusion Capacity Tests

This test determines how well oxygen has traveled from the lungs into the bloodstream. A technologist will guide you in breathing through a special mouthpiece connected to a device that will measure the components of exhaled gas.

Lung Volume Measurement

Lung volume measurement reveals how much air the lungs can hold and how the air is dispersed throughout the lungs. It also measures how much air remains in the lungs after a full exhalation. This quantity of air is referred to as residual volume (RV). We use two methods to determine lung volume.

  • Body Plethysmography
    You will sit in a Plexiglas chamber and breathe into a sensor tube. Gently panting in and out on the tube causes pressure changes that are translated into gas volume measurements.
  • Gas Dilution
    You breathe normally into a chamber containing a trace amount of helium. The helium is diluted by air from the lungs. The lung volumes are calculated from the final stable dilution value of helium.

Methacholine Challenge

A methacholine challenge (MCT) is used to determine whether you have asthma. You will inhale a low dose of a drug called methacholine, and then perform spirometry (breathe into a special meter) to see if there is a subsequent decrease in lung function. Methacholine doses are incrementally increased until there is a either a change in lung function or the testing protocol is completed. The technician is trained to notice any changes from the baseline spirometric values. The MCT is always followed by administration of a bronchodilator which reverses the effects of methacholine. Finally, spirometry is performed once again to confirm that lung function is at pre-MCT values.

Exercise Testing

Exercise testing can help physicians understand the limits of your lung function. Several types of exercise testing are performed at the RWJUH Pulmonary Laboratory.

  • The Six-Minute Walk Test
    The six-minute walk test is a simple but effective method to gauge overall wellness. A course of 100 feet is marked in a well-lit, tile-floored hallway. At the start of a timer, you will walk briskly back and forth on the 100-foot course. The goal is to establish how much distance you can cover in six minutes’ time.
  • Complex Pulmonary Exercise Tests
    Complex pulmonary exercise tests (CPETs) provide an in-depth look at the physiology of a patient during exercise. This valuable test is administered to discover the cause of shortness of breath on exertion, to see if a patient can tolerated lung surgery, or to monitor the progression of heart failure. You will ride a stationary bike (ergometer) and breathe through a tube while exercising. This enables the lab to measure how much oxygen is consumed with progressively harder levels of resistance on the bike (it feels like pedaling up hill). Other important values are recorded during the exercise, such as electrocardiogram (EKG), blood pressure, oxygen saturation, and arterial blood sampling.
  • Exercise Test for Bronchospasm
    This test uses a stationary bike as well. The patient pedals against gradually increasing resistance until their heart rate is 80 percent of the predicted maximum rate. That level is maintained for six minutes and then exercise is stopped. Spirometry testing follows, performed at timed intervals after exercise (1, 3, 5, 10, and 15 minutes post exercise). This is useful for determining if exercise-induced asthma is the cause of the patient’s breathing problem.
  • Arterial Blood Gas Test
    A small blood sample is taken from an artery (generally in the wrist where the pulse is often taken) before and after exercise. This measurement facilitates direct measurement of oxygen, carbon dioxide and pH values in arterial blood.

Pentamidine Aerosol Therapy

In addition to lung testing, pentamidine aerosol therapy is administered in the Pulmonary Function Lab. This therapy is used to prevent pneumonia that might occur in patients with compromised immune systems (from cancer treatment, post-transplant immunosuppression, or immune disorders, for example).

Learn more about Pulmonary and Critical Care Medicine at Robert Wood Johnson University Hospital.