Guidelines › External cause codes

External cause codes

Official text from the FY2027 ICD-10-CM Official Guidelines for Coding and Reporting. The wording is quoted exactly.

Guidelines I.C.20.a.2; I.C.20.a.6

“An external cause code can never be a principal (first-listed) diagnosis.”

“Assign the external cause code, with the appropriate 7th character (initial encounter, subsequent encounter or sequela) for each encounter for which the injury or condition is being treated.”

“assignment of the 7th character for external cause should match the 7th character of the code assigned for the associated injury or condition for the encounter.”

Where this applies

7,461 billable codes. Source: FY 2027 ICD-10-CM Official Guidelines for Coding and Reporting, effective October 1, 2026. Full Guidelines (PDF, CMS)