2027 ICD-10-CM Diagnosis Code Y99External cause status

ICD-10-CM Codes›V01–Y99›Y90-Y99›Y99

ICD-10-CM Y99
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

Y99 is a non-billable ICD-10-CM category code for external cause status, so it cannot be submitted on claims. Use a more specific code from this category instead, such as Y99.0, Y99.1, Y99.2, and Y99.8.

Code Identity

ICD-10-CM Code
Y99
Billable Status
No — Non-Billable Category
Code Describes
External cause status
Short Description
External cause status
Same as the full description in the CMS dataset.
Chapter
Y90-Y99
Supplementary factors related to causes of morbidity classified elsewhere

Code Classification

ChapterV01–Y99External causes of morbidity and mortality
SectionY90-Y99Supplementary factors related to causes of morbidity classified elsewhere
CategoryY99External cause status
This CodeY99External cause status

Specific Coding for External cause statusOverview

Non-specific codes like Y99 require more characters. Use one of these billable codes instead:

  • Use Y99.0 for Civilian activity done for income or pay

  • Use Y99.1 for Military activity

  • Use Y99.2 for Volunteer activity

  • Use Y99.8 for Other external cause status

  • Use Y99.9 for Unspecified external cause status

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to Y99: its own notes plus those printed at block Y90-Y99 and Chapter 20. A note printed at a category, block or chapter applies to every code under it.

Notes

General instructions on how these codes are used.

On Y99 itself
  • A single code from category Y99 should be used in conjunction with the external cause code(s) assigned to a record to indicate the status of the person at the time the event occurred.
From Block Y90-Y99 Supplementary factors related to causes of morbidity classified elsewhere applies to 334 codes
  • These categories may be used to provide supplementary information concerning causes of morbidity. They are not to be used for single-condition coding.
From Chapter 20 (V00-Y99) External causes of morbidity and mortality applies to 7,461 codes
  • This chapter permits the classification of environmental events and circumstances as the cause of injury, and other adverse effects. Where a code from this section is applicable, it is intended that it shall be used secondary to a code from another chapter of the Classification indicating the nature of the condition. Most often, the condition will be classifiable to Chapter 19, Injury, poisoning and certain other consequences of external causes (S00-T88). Other conditions that may be stated to be due to external causes are classified in Chapters I to XVIII. For these conditions, codes from Chapter 20 should be used to provide additional information as to the cause of the condition.

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name Y99, its category, or a range that includes it.

Notes 1

These notes mention Y99.

  • Y93 Activity codes
    Category Y93 is provided for use to indicate the activity of the person seeking healthcare for an injury or health condition, such as a heart attack while shoveling snow, which resulted from, or was contributed to, by the activity. These codes are appropriate for use for both acute injuries, such as those from chapter 19, and conditions that are due to the long-term, cumulative effects of an activity, such as those from chapter 13. They are also appropriate for use with external cause codes for cause and intent if identifying the activity provides additional information on the event. These codes should be used in conjunction with codes for external cause status (Y99) and place of occurrence (Y92).

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About Y99Overview

What is the ICD-10 code for external cause status?

Y99 is the ICD-10-CM category for external cause status, but it is a non-billable header: claims need a more specific code from this category, listed on this page.

Is Y99 (External cause status) a billable code?

No. This is a category header that groups the codes for external cause status, and headers cannot be submitted on claims. Claims for external cause status need a more specific code from this category, such as Y99.0, Y99.1, and Y99.2.