Medical Coding Practice Test 2026 - Free Medical Coding Practice Questions and Study Guide

Fifth-digit sub-classifications in ICD-9-CM focus on etiology, site, or manifestation. This means that these sub-classifications provide more detailed information about the cause (etiology), location (site), or characteristics (manifestation) of the patient's condition or illness. By using fifth-digit codes, medical coders can specify and differentiate between various aspects of a diagnosis, which is essential for accurate billing and tracking of diseases or health conditions. Patient demographics, family medical history, and environmental factors are not typically the focus of fifth-digit sub-classifications in ICD-9-CM.