Certified Coding Associate (CCA) Practice Exam 2025 - Free Coding Associate Practice Questions and Study Guide

The term for four-digit ICD-9-CM diagnosis codes is "subcategory codes." These codes provide a more specific classification of the diagnosis compared to three-digit codes, allowing for greater detail in medical documentation. The structure of ICD-9-CM includes categories at the three-digit level, which represent a broad classification of diseases or conditions. The additional fourth digit narrows down the diagnosis to enhance specificity, providing crucial information for both clinical and billing purposes.

Subcategory codes are integral in coding as they can represent variations in the severity of a condition, specific manifestations, or particular anatomical locations, which are important for both treatment and statistical reporting. This coding specificity is essential for accurate diagnosis representation, reimbursement processes, and health data analytics.

The other terms mentioned do not accurately describe the four-digit ICD-9-CM diagnosis codes. While "diagnostic codes" is a general term that may refer to all codes in the system, it does not specifically denote the four-digit ones. "Subclass codes" and "subclassification codes" are not officially recognized terms in the context of ICD-9-CM for this level of coding either, which further validates why "subcategory codes" is the correct designation.