CPT code 94726 encompasses the procedure of plethysmography performed to determine lung volumes and, when applicable, airway resistance. This code specifies the components included when this diagnostic test is administered.
Understanding CPT Code 94726
The Current Procedural Terminology (CPT) code 94726 is used to identify a comprehensive pulmonary function test. It specifically covers the measurements taken during a body plethysmography study.
| Code | Description |
|---|---|
| 94726 | Plethysmography for determination of lung volumes and, when performed, airway resistance |
What is Plethysmography?
Plethysmography, often referred to as a "body box" test, is an advanced pulmonary function test that measures the total amount of air in the lungs and the ease with which air moves in and out. Unlike basic spirometry, which measures airflow during breathing maneuvers, plethysmography uses a sealed chamber to precisely assess lung volumes that cannot be exhaled, such as residual volume, and to determine how much resistance the airways present to airflow.
Key Measurements Involved
CPT code 94726 details two primary measurements:
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Determination of Lung Volumes: This aspect of the test accurately measures various lung capacities and volumes, including:
- Total Lung Capacity (TLC): The total amount of air the lungs can hold after a maximum inhalation.
- Functional Residual Capacity (FRC): The volume of air remaining in the lungs after a normal exhalation.
- Residual Volume (RV): The amount of air left in the lungs after a maximal exhalation.
These measurements are crucial for identifying restrictive lung diseases, where lung expansion is limited, or hyperinflation seen in obstructive conditions.
-
Airway Resistance (when performed): This measures the pressure difference required to move air into and out of the lungs, indicating how much the airways resist airflow. It helps determine if the airways are narrowed or obstructed. This component is performed if clinically indicated during the same plethysmography session. High airway resistance can be a key indicator of conditions like asthma or chronic obstructive pulmonary disease (COPD).
Why are these measurements important?
The data collected via plethysmography provides invaluable insights into a patient's respiratory health. These detailed measurements aid in:
- Diagnosing Lung Diseases: Helps differentiate between obstructive lung diseases (e.g., asthma, COPD) and restrictive lung diseases (e.g., pulmonary fibrosis).
- Assessing Disease Severity: Quantifies the extent of lung impairment.
- Monitoring Treatment Effectiveness: Tracks changes in lung volumes and airway resistance in response to medication or other interventions.
- Pre-operative Assessment: Evaluates lung function before surgery, especially for thoracic or abdominal procedures.
