The document outlines the coding procedures for pulmonary function tests (PFTs), including the various types of tests like spirometry and lung volume determination, each with specific CPT codes for accurate billing. It emphasizes the importance of using appropriate codes to ensure reimbursement and compliance with Medicare's criteria for reasonable and necessary care. Additionally, it provides details on ICD-10-CM codes for respiratory conditions and stresses the need for proper documentation of medical necessity in patient records.