Which coding system is primarily used for medical diagnoses in the United States?

The coding system primarily used for medical diagnoses in the United States is ICD-10-CM. This system, which stands for the International Classification of Diseases, 10th Revision, Clinical Modification, is specifically designed to classify and code diagnoses, symptoms, and procedures related to healthcare services.

ICD-10-CM is utilized by healthcare providers to report patient diagnoses in a standardized way, which facilitates the collection of data for research, resource allocation, epidemiology, and health management. It provides a comprehensive framework that allows for detailed coding of a wide variety of medical conditions, ensuring clarity and consistency across the healthcare system.

In contrast, the other coding systems serve different purposes. CPT (Current Procedural Terminology) is primarily used for coding medical procedures and services rather than diagnoses. HCPCS (Healthcare Common Procedure Coding System) includes codes for non-physician services and supplies, while DRG (Diagnosis-Related Group) is a system used for classifying hospital cases into groups for payment purposes, rather than for coding specific diagnoses. Thus, ICD-10-CM stands out as the correct answer for coding medical diagnoses.