The ICD-10-CM Official Guidelines for Coding and Reporting sets the precedent of rules that all diagnostic coders must abide by. Section I.C. covers the chapter-specific guidelines. These offer detailed information about various conditions that require more thorough reporting guidance than the general guidelines provide. Reading the guidelines in their entirety is incredibly important, but this series of articles aims to summarize and highlight key points. This article will break down the official guidelines for Chapters 11–13.

As always, both current and previous versions of the ICD-10-CM guidelines are stored on the CMS website. Make sure to use the correct version when reporting retrospective claims or conducting audits of previous years. Coders should also use Tabular List and National Correct Coding Initiative edits in tandem with these guidelines to more closely align with national coding requirements.

• Chapter 11: Diseases of the Digestive System (K00-K95)
• Chapter 12: Diseases of the Skin and Subcutaneous Tissue (L00-L99)
• Chapter 13: Diseases of the Musculoskeletal System and Connective Tissue (M00-M99)