ICD 10 Study Guide: Chapter 4 Endocrine, Nutritional & Metabolic Diseases:

ICD-10-CM Chapter 4 covers codes E00 through E89 — conditions affecting the endocrine system (glands and hormones), nutritional status, and metabolism. This chapter contains some of the most frequently coded and most heavily tested conditions on the CPC® exam, especially diabetes mellitus.

The chapter is unique because diabetes mellitus codes use a combination code structure that captures both the type of diabetes and its associated complications in a single code. Understanding this structure is absolutely critical for exam success.