CMAA Practice Exam 2026 – Complete Guide for Exam Prep

The International Classification of Diseases (ICD) is the coding system used for diagnoses in medical billing. This system provides standardized codes for a wide variety of diseases, conditions, and other health-related issues, allowing healthcare providers to accurately document patient diagnoses. It is pivotal in ensuring that diagnoses are universally understood and can effectively support medical billing, research, and public health tracking.

ICD codes play a critical role in linking the patient's conditions to the services rendered, thereby facilitating the billing process with insurers. The codes are comprehensive and cover both acute and chronic conditions, making them essential for effective communication between providers and payers.

Other coding systems, such as Current Procedural Terminology (CPT) and Healthcare Common Procedure Coding System (HCPCS), are primarily focused on coding medical procedures and services rather than the diagnoses themselves. The National Drug Code (NDC) is utilized specifically for the identification of medications and their manufacturers, thus not applicable to diagnosis coding. Understanding the distinct roles of these coding systems is essential for effective medical billing practice.