II.A

Codes for symptoms, signs, and ill-defined conditions

Codes for symptoms, signs, and ill-defined conditions from Chapter 18 are not to be used as principal diagnosis when a related definitive diagnosis has been established.

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.