Chapter 20: External Causes of Morbidity (V00-Y99)
The external causes of morbidity codes should never be sequenced as the first-listed or principal diagnosis. External cause codes are intended to provide data for injury research and evaluation of injury prevention strategies.
These codes capture how the injury or health condition happened (cause), the intent (unintentional or accidental; or intentional, such as suicide or assault), the place where the event occurred the activity of the patient at the time of the event, and the person’s status (e.g., civilian, military). There is no national requirement for mandatory ICD-10-CM external cause code reporting.
Unless a provider is subject to a state-based external cause code reporting mandate or these codes are required by a particular payer, reporting of ICD-10-CM codes in Chapter 20, External Causes of Morbidity, is not required.
In the absence of a mandatory reporting requirement, providers are encouraged to voluntarily report external cause codes, as they provide valuable data for injury research and evaluation of injury prevention strategies.
In this section
- I.C.20.aGeneral External Cause Coding Guidelines
- I.C.20.bPlace of Occurrence Guideline
- I.C.20.cActivity Code
- I.C.20.dPlace of Occurrence, Activity, and Status Codes Used with other
- I.C.20.eIf the Reporting Format Limits the Number of External Cause Codes
- I.C.20.fMultiple External Cause Coding Guidelines
- I.C.20.gChild and Adult Abuse Guideline
- I.C.20.hUnknown or Undetermined Intent Guideline
- I.C.20.iSequelae (Late Effects) of External Cause Guidelines
- I.C.20.jTerrorism Guidelines
- I.C.20.kExternal Cause Status
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.