Spirometry is a pulmonary function test that measures how quickly the lungs can move air in and out as well as how much air the lungs can displace. While other methods can be used to test lung function, including gas diffusion tests, residual volume measurement, body plethysmography, inhalation challenge tests and exercise stress tests, spirometry is most routinely used. When a patient has an abnormal spirometry test result, other more complex and expensive tests may be used to follow up.

Who should be tested?

  • Smokers over age 40
  • Patients with shortness of breath, chronic cough or frequent colds
  • Patients who have allergic rhinitis
  • Patients exposed to occupational dust or chemicals
  • Patients suspected to have asthma or cardiopulmonary disease
  • Patients whose asthma must be monitored
  • Patients who have wheezing.

How do spirometers work?

In a spirometry test, the patient breathes into a tight-fitting mouthpiece connected to the spirometer. Some test measurements require normal, quiet breathing. Others have the patient take a deep breath and, when told, exhale the air for as long, hard and fast as possible.

The spirometer records the amount and the rate of air that is breathed in and out over a specific period. Some spirometers have a transducer built in, while others require the patient to hold it. The transducer measures the pressure differential. Data is entered into an algorithm within the device, which calculates measurements. Most manufacturers use an algorithm that follows the American Thoracic Society guidelines.

Indications for spirometry:

Spirometry may be used to diagnose various lung diseases, such as asthma, bronchitis or emphysema; to determine the cause for shortness of breath; or to measure whether occupational exposure to contaminants affects lung function. Spirometry often is used to assess such therapeutic interventions as bronchodilator therapy or steroid treatment.

Some indications generally are not covered by Medicare, according to the American Thoracic Society. These include the following:

  • Screening smokers or individuals exposed to occupational hazards for pulmonary disease
  • Assessing health status before enrolling the patient in strenuous physical activity programs
  • Assessing the patient as part of a rehabilitation program
  • Assessing patient risks as part of an insurance evaluation
  • Assessing individuals for legal reasons, such as social security or personal injury lawsuits.

Spirometry measurements:

Spirometry measures the volume of air exhaled or inhaled over a specific time period. Some measurements provided by the test include:

  • FEV1 - Forced expiratory volume in the first second
  • FVC - Forced vital capacity
  • FEV6 - Forced expiratory volume after six seconds
  • PEF - Peak expiratory flow
  • VC - Vital capacity.

Advances in technology

Early models were volume driven and required the physician to measure all data points himself. Todays spirometers are smaller and flow based, thus reducing the risk of cross contamination. Spirometers now use ultrasound technology, which is independent of heat, humidity, gas composition and pressure, and helps eliminate errors caused by these variables. Ultrasound technology also eliminates the need for moving parts. There are no codes to enter, no screens to catch sputum and no disposables to calibrate. All interpretations and data calculations are done automatically within the microprocessor.

Spirometers can be customized to provide more or less information, depending on the needs of the physicians practice. Today, data management reports can display data in graphical and tabular formats. Reports display predicted and actual changes in values. And, database queries help identify patients with common attributes.

Who are potential customers?

  • Family practitioners
  • Primary care physicians
  • Pediatricians
  • Pulmonologists
  • Allergists or asthma specialists
  • Cardiologists
  • Internists
  • Occupational medicine practitioners
  • General practitioners working in clinics or hospitals.

CPT Code Test Description National Average
94010 Spirometry Complete, includes graphic record total and timed vital capacity, expiratory flow rate measurement(s) with or without voluntary ventilation. $36.80
94060 Bronchodilation Responsiveness, spirometry as in 94010, pre- and post bronchodilator or exercise $62.70
94070 Bronchospasm Provocation Evaluation, multiple spirometric determinations as in 94010, with administered agents (e.g. antigen(s), cold air, methacholine). $61.54
94200 Lung Function Test (MBC/MVV) - Maximum Voluntary Ventrilation $25.85
94620 Pulmonary Stress Test/Simple (Prolonged exercise with pre and post test spirometry) $57.53
94016 Review Patient Spirometry, 30 day period of time; physician review and interpretation only $26.20
94375 Respiratory Flow Volume Loop $40.44
95070 Inhalation Bronchial Challeng Testing, (not including necessary pulmonary function tests), with histamine, methacholine or similar compounds. $31.33
95071 Inhalation Bronchial Challenge Testing, (not including necessary pulmonary function tests), with specified antigens or gases $36.07
94664 Bronchodilator Administration, demonstration and/or evaluation of patient utilization of an aerosol generator, nebulizer, meter dose inhaler or IPPB device. $17.85