94010

Spirometry, including DLCO (diffusing capacity of lung for carbon monoxide)

This CPT code represents a comprehensive pulmonary function test that includes both spirometry and the measurement of the diffusing capacity of the lung for carbon monoxide (DLCO). Spirometry evaluates ventilatory function by measuring lung volumes, flow rates, and the dynamics of breathing, assessing how much air a person can inhale and exhale, and how quickly. The DLCO, also known as transfer factor (TLCO), assesses the efficiency of gas exchange across the alveolar-capillary membrane, indicating the integrity of this barrier and the pulmonary vascular bed, as well as the hemoglobin concentration. This combined test provides a thorough evaluation of both obstructive and restrictive lung diseases and the lung's ability to transfer gases into the bloodstream.

Clinical Indications

  • Diagnosis and monitoring of obstructive lung diseases (e.g., asthma, chronic obstructive pulmonary disease [COPD])
  • Diagnosis and monitoring of restrictive lung diseases (e.g., interstitial lung disease, pulmonary fibrosis, sarcoidosis)
  • Evaluation of dyspnea (shortness of breath) or unexplained cough
  • Preoperative assessment, particularly for thoracic and abdominal surgeries
  • Assessment of occupational or environmental lung disease
  • Monitoring the effectiveness of therapeutic interventions for lung diseases
  • Evaluation of drug toxicity affecting pulmonary function (e.g., amiodarone, methotrexate, bleomycin)
  • Assessment of lung involvement in systemic diseases (e.g., rheumatoid arthritis, systemic lupus erythematosus)
  • Quantification of functional impairment for disability assessment

Procedure Steps

  1. Patient preparation, including explaining the procedure, ensuring comfort, and confirming abstention from bronchodilator use prior to the test (if required by protocol).
  2. Calibration and quality control checks of the spirometer and DLCO equipment.
  3. Performance of spirometry maneuvers: The patient takes a maximal inspiration, then exhales as hard and fast as possible into a mouthpiece connected to the spirometer until no more air can be expelled. This maneuver is repeated to obtain reproducible and acceptable efforts (typically a minimum of three).
  4. Measurements obtained from spirometry include Forced Vital Capacity (FVC), Forced Expiratory Volume in 1 second (FEV1), FEV1/FVC ratio, and Forced Expiratory Flow between 25% and 75% of FVC (FEF25-75%).
  5. Performance of DLCO maneuver: The patient breathes a gas mixture containing a small, known concentration of carbon monoxide and a tracer gas (e.g., helium), holds their breath for approximately 10 seconds, and then exhales rapidly. The exhaled gas is analyzed to determine the amount of carbon monoxide absorbed.
  6. Measurements obtained from DLCO include the diffusing capacity (DLCO or TLCO) and corrected values (e.g., for hemoglobin concentration).
  7. Data analysis and interpretation by a qualified physician or healthcare professional, comparing results to predicted normal values based on age, sex, height, and ethnicity.

Coding Guidelines

  • Do not report CPT code 94010 in conjunction with codes 94011, 94012, 94013, 94060, 94070, 94375, 94726, or 94729 when performed on the same date of service.
  • CPT code 94010 includes the technical component and the professional interpretation of both spirometry and DLCO.
  • The physician's interpretation and report must be fully documented in the patient's medical record, including the clinical indication, raw data, measurements obtained, comparison to predicted values, and an overall assessment/conclusion.
  • Medical necessity for performing both spirometry and DLCO must be clearly documented.
  • This code typically requires direct physician supervision for the technical component and independent interpretation.
  • For tests performed at different times or for different reasons, separate codes (e.g., 94060 for spirometry with bronchodilator, 94729 for DLCO alone) may be appropriate, but not 94010 if components are split.
  • This service has a global period of 'XXX' (global concept does not apply).

Associated ICD-10 Codes