Which coding system is primarily used for reporting outpatient services?

The coding system primarily used for reporting outpatient services is the Current Procedural Terminology (CPT). This system is designed to represent a broad range of medical services and procedures conducted in outpatient settings, making it essential for proper documentation and billing of these services.

CPT codes allow healthcare providers to communicate their services effectively to insurance companies and other payers. It includes codes for evaluation and management services, surgical procedures, and various diagnostic tests, thereby covering a wide range of outpatient care encounters.

Other coding systems, while important in their specific contexts, do not serve the same primary function in outpatient settings. For instance, ICD-10 codes are primarily used for diagnosing conditions rather than procedures, while HCPCS codes are often used for equipment, supplies, and certain services not covered by CPT. The National Drug Code (NDC) is specific to identifying medications rather than general outpatient services. Therefore, CPT is the correct choice as it directly relates to the procedural coding necessary for reporting outpatient services.