ICD-10-CM External Cause Index · FY 2026 314 Terms
2026 ICD-10-CM External Cause of Injuries Index ICD-10-CM
The External Cause of Injuries Index is the alphabetical key to chapter 20 of ICD-10-CM. It files 314 main terms and 8,090 index entries describing how an injury happened: the event, the vehicle or object involved, the place of occurrence, and the activity. Each line points to a V00-Y99 external cause code that is reported after the injury code itself. Look up the event, walk the indented modifiers, then verify the code on its code page. The ICD-10-CM lookup tool searches the same data by keyword.
✓ Built from the official CMS FY 2026 index fileEffective Oct 1, 2025 – Sep 30, 2026
314
Main Terms
8,090
Index Entries
22
Letters
FY 2026
Dataset
Step 1
Find the event
How it happened: Fall, Accident, Bite, Assault
Step 2
Walk the indents
Each level adds vehicle, object, place, or intent detail
Step 3
Report it second
External cause codes follow the injury code; check 7th characters on the code page
Browse the External Cause Index A to W
A22 main terms
- Abandonment (causing exposure to weather conditions) (with intent to injure or kill) NEC
- Abuse (adult) (child) (mental) (physical) (sexual)
- Accident (to)
- Acid throwing (assault)
B20 main terms
- Barotitis, barodontalgia, barosinusitis, barotrauma (otitic) (sinus)
- Battered (baby) (child) (person) (syndrome)
- Bayonet wound
- Bean in nose
C29 main terms
- Caisson disease
- Campfire (exposure to) (controlled)
- Capital punishment (any means)
- Car sickness
D17 main terms
- Decapitation (accidental circumstances) NEC
- Dehydration from lack of water
- Deprivation
- Derailment (accidental)
E15 main terms
- Earth (surface) movement NEC
- Earth falling (on)
- Earthquake (any injury)
- Effect (s) (adverse) of
H15 main terms
- Hailstones, injured by
- Hanged herself or himself
- Hanging (accidental)
- Heat (effects of) (excessive)
I19 main terms
- Ictus
- Ignition (accidental)
- Immersion (accidental)
- Implantation of quills of porcupine
K5 main terms
- Kicked by
- Kicking
- Killed, killing (accidentally) NOS
- Kneeling (prolonged) (static)
L12 main terms
- Laceration NEC
- Lack of
- Landslide (falling on transport vehicle)
- Late effect
M16 main terms
- Malfunction (mechanism or component) (of)
- Maltreatment
- Mangled (accidentally) NOS
- Manhandling (in brawl, fight)
N5 main terms
- Nail
- Neglect (criminal) (homicidal intent)
- Noise (causing injury) (pollution)
- Nonadministration (of)
P18 main terms
- Parachute descent (voluntary) (without accident to aircraft)
- Pecked by bird
- Perforation during medical or surgical treatment as misadventure
- Perpetrator, perpetration, of assault, maltreatment and neglect (by)
R13 main terms
- Radiation (exposure to)
- Range disease
- Rape (attempted) (confirmed)
- Rat bite
S43 main terms
- Saturnism
- Scald, scalding (accidental) (by) (from) (in)
- Scratched by
- Seasickness
U3 main terms
- Underdosing of necessary drugs, medicaments or biological substances
- Undetermined intent (contact) (exposure)
- Use of hand as hammer
V4 main terms
- Vibration (causing injury)
- Victim (of)
- Volcanic eruption (any injury)
- Vomitus, gastric contents in air passages (with asphyxia, obstruction or suffocation)
W9 main terms
- Walked into stationary object (any)
- War operations (injuries to military personnel and civilians during war, civil insurrection and peacekeeping missions) (by) (from) (involving)
- Washed
- Weather exposure NEC
Reading the Index: Abbreviations and Conventions
NEC NEC "Not Elsewhere Classifiable"This abbreviation in the Alphabetic Index represents "other specified". When a specific code is not available for a condition, the Alphabetic Index directs the coder to the "other specified” code in the Tabular List.
NOS NOS "Not Otherwise Specified"This abbreviation is the equivalent of unspecified.
sevenChrNote 7th Character NoteCertain ICD-10-CM categories have applicable 7th characters. The applicable 7th character is required for all codes within the category, or as the notes in the Tabular List instruct. The 7th character must always be the 7th character in the data field. If a code that requires a 7th character is not 6 characters, a placeholder X must be used to fill in the empty characters.
excludes1 Type 1 ExcludesA type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
excludes2 Type 2 ExcludesA type 2 excludes note represents "Not included here". An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.
and "And"The word "and" should be interpreted to mean either "and" or "or" when it appears in a title.
with "With"The word "with" should be interpreted to mean "associated with" or "due to" when it appears in a code title, the Alphabetic Index, or an instructional note in the Tabular List.
The word "with" in the Alphabetic Index is sequenced immediately following the main term, not in alphabetical order.
see also "See Also"A "see also" instruction following a main term in the Alphabetic Index instructs that there is another main term that may also be referenced that may provide additional Alphabetic Index entries that may be useful. It is not necessary to follow the "see also" note when the original main term provides the necessary code.
see "See"The "see" instruction following a main term in the Alphabetic Index indicates that another term should be referenced. It is necessary to go to the main term referenced with the "see" note to locate the correct code.
codeAlso Code AlsoA "code also" note instructs that two codes may be required to fully describe a condition, but this note does not provide sequencing direction.
inclusionTerm Inclusion TermsThese terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
includes IncludesThis note appears immediately under a three character code title to further define, or give examples of, the content of the category.
codeFirst Code FirstCertain conditions have both an underlying etiology and multiple body system manifestations due to the underlying etiology. For such conditions, the ICD-10-CM has a coding convention that requires the underlying condition be sequenced first followed by the manifestation. Wherever such a combination exists, there is a "use additional code" note at the etiology code, and a "code first" note at the manifestation code. These instructional notes indicate the proper sequencing order of the codes, etiology followed by manifestation.
sevenChrDef 7th CharacterIndicates that a seventh character is to be assigned to codes in a subcategory.
useAdditionalCode Use Additional CodeThe “use additional code” indicates that a secondary code could be used to further specify the patient’s condition. This note is not mandatory and is only used if enough information is available to assign an additional code.
Questions About the Index
What is the ICD-10-CM External Cause of Injuries Index?
It is the alphabetical key to the external cause codes in chapter 20 (V00-Y99). Events are filed under main terms like Accident, Fall, or Assault, with indented modifiers for the vehicle, object, place, and intent, and each line points to the external cause code that fits that combination. CMS publishes it with every fiscal year release.
Are external cause codes required?
They are never reported alone and never as the principal diagnosis: the injury code comes first and the external cause code follows it. There is no national requirement to report them unless a state or a payer mandates it, but CMS encourages voluntary reporting because the data drives injury prevention research.
Where do place of occurrence and activity codes fit?
The index carries them under their own main terms. Place of occurrence entries point to Y92 codes, Activity entries point to Y93 codes, and both are reported once, at the initial encounter, alongside the external cause code that describes the event itself.
Related References
Source: Centers for Medicare & Medicaid Services, FY 2026 ICD-10-CM External Cause of Injuries Index release files, effective October 1, 2025 through September 30, 2026.
