I.C.20.a
General External Cause Coding Guidelines
This is a section heading — the guidance lives in the subsections below.
In this section
- I.C.20.a.1)Used with any code in the range of A00.0-T88.9, Z00-Z99
- I.C.20.a.2)External cause code used for length of treatment
- I.C.20.a.3)Use the full range of external cause codes
- I.C.20.a.4)Assign as many external cause codes as necessary
- I.C.20.a.5)The selection of the appropriate external cause code
- I.C.20.a.6)External cause code can never be a principal diagnosis
- I.C.20.a.7)Combination external cause codes
- I.C.20.a.8)No external cause code needed in certain circumstances
ICD-10-CM Official Guidelines for Coding and Reporting, FY 2026 (effective October 1, 2025). Published by CMS and NCHS. Reproduced for reference — always verify against the official CMS release.