ICD-10 External Cause Codes (V00-Y99) are secondary codes that capture specific details about an injury or health event.Though it is not mandatory to use external cause codes, medical coding outsourcing companies nevertheless do so because ICD-10 guidelines encourage voluntary reporting of these codes to “provide valuable data for injury research and evaluation of injury prevention strategies”. Further, as an article published by the American Academy of Professional Coders (AAPC) notes, using external cause codes to tell the whole story could help streamline claims submission and payment settlement.

Why and How to Use ICD-10 External Causes Codes

ICD-10 External Cause Codes (V00-Y99)

External Causes of Injury for Transport Accidents

  • V00-V09 Pedestrian injured in transport accident
  • V10-V19 Pedal cycle rider injured in transport accident
  • V20-V29 Motorcycle rider injured in transport accident
  • V30-V39 Occupant of three-wheeled motor vehicle injured in transport accident
  • V40-V49 Car occupant injured in transport accident
  • V50-V59 Occupant of pick-up truck or van injured in transport accident
  • V60-V69 Occupant of heavy transport vehicle injured in transport accident
  • V70-V79 Bus occupant injured in transport accident
  • V80-V89 Other land transport accidents
  • V90-V94 Water transport accidents
  • V95-V97 Air and space transport accidents
  • V98-V99 Other and unspecified transport accidents

Injuries Due to Falls and Exposure

  • W00-W19 Slipping, tripping, stumbling and falls
  • W20-W49 Exposure to inanimate mechanical forces
  • W50-W64 Exposure to animate mechanical forces
  • W65-W74 Accidental non-transport drowning and submersion
  • W85-W99 Exposure to electric current, radiation and extreme ambient air temperature and pressure

Injuries Due to Self-Harm, Assault, or Undetermined Intent

  • X00-X08 Exposure to smoke, fire and flames
  • X10-X19 Contact with heat and hot substances
  • X30-X39 Exposure to forces of nature
  • X50-X50 Overexertion and strenuous or repetitive movements
  • X52-X58 Accidental exposure to other specified factors
  • X71-X83 Intentional self-harm
  • X92-Y09 Assault

Legal, Military, and Medical Causes and Supplementary Factors

  • Y21-Y33 Event of undetermined intent
  • Y35-Y38 Legal intervention, operations of war, military operations, and terrorism
  • Y62-Y69 Misadventures to patients during surgical and medical care
  • Y70-Y82 Medical devices associated with adverse incidents in diagnostic and therapeutic use
  • Y83-Y84 Surgical and other medical procedures as the cause of abnormal reaction of the patient, or of later complication, without mention of misadventure at the time of the procedure
  • Y90-Y99 Supplementary factors related to causes of morbidity classified elsewhere

Significance of Reporting External Cause Codes

Reporting external causes of morbidity is important because:

  • Wounds, injuries, poisonings, and adverse effects of medications require reporting of the circumstances around them as the causes may be varied.
  • External cause codes identify the cause of an injury or health condition, the intent (accidental or intentional), the place where the incident occurred, the activity of the patient at the time of the incident, and the patient’s status (such as civilian or military).
  • They play a role during both the initial time of care and follow-up treatment.
  • These secondary codes provide data for injury research and evaluation of strategies for injury prevention. For instance, as an ICD-10 Monitor report points out, the injury-related information captured via codes allows the CDC to track valuable information and states to assess injury prevalence, trends, and other risk factors and improve injury prevention and control. The report also notes that external cause codes are also used by
    • Insurance companies (especially in relation to worker’s compensation claims)
    • State legislators to improve safety laws
    • The media (to inform the public)
    • State agencies, such as transportation departments and elementary and secondary school departments, and
    • Health and community advocates
    • Individual organizations to improve internal processes and facilities
  • Examples of Reporting External Cause Codes

    An external cause code may be used with any code in the range of A00.0-T88.9, Z00-Z99, classification that is a health condition due to an external cause. The external cause codes in the V00 to V99 category are classified into 12 groups, which reflect the person’s mode of transport. The first two characters of the code identify the vehicle, such as V1 for pedal cycle rider, V2 for motorcycle rider, V4 for car occupant, and V5 for occupant of pick-up truck or van. AAPC provides the following example of using an external cause code to report the circumstances around a transport accident:

    V43.51xA Car driver injured in collision with sport utility vehicle in traffic accident, initial encounter

    The American Academy of Pediatrics (AAP) provides an example of an event where a Y code would come into play:

    A 14-year-old presents with pain in the right wrist and elbow. After taking an extensive history and exam, the physician determines that the child has lateral epicondylitis. The child and parent admit the child has used a handheld video game excessively. The physician determines that the cause is due to the repetitive motion of the handheld gaming devices.

    Primary condition: M77.11Lateral epicondylitis, right elbow
    Activity: Y93.C2 Activity, handheld interactive electronic device

    Reporting Guidelines

    Here are some key points to note when using Chapter 20 codes:

    • External cause codes are never reported as primary, that is they cannot be assigned as a principal diagnosis.
    • They never reported alone.
    • They can be reported with any condition due to an external cause and are not limited to injuries or poisonings.
    • Use the full range of external cause codes to completely describe the cause, intent, place of occurrence and if applicable, the activity of the patient at the time of the event, and the patient’s status.
    • Multiple external cause codes may be used to fully explain each cause.
    • If only one external code can be reported, use the code most related to the principal diagnosis.
    • Code to accidental if the intent or cause of an injury or health event is unknown.
    • No external cause code is necessary if the external cause and intent are included in a code from another chapter, for e.g., T36.0X1- poisoning by penicillin, accidental (unintentional).
    • Unless otherwise specified, all transport accidents are accidental (intent).
    • Place of occurrence codes should be reported after other external cause codes.
    • Place of occurrence codes are typically only reported on the initial encounter for treatment and do not have 7th characters.
    • Do not code unspecified place of occurrence if the place is not specified or is not applicable.
    • Activity codes are used only once at the initial encounter for treatment and are not applicable to poisonings, adverse effects, misadventures or sequel.
    • Unspecified activity should not be coded if the activity is not stated, unless facility policy dictates otherwise

    While there is no national requirement for reporting external cause codes, it is necessary in some states. A 2017 For The Record article noted that the Louisiana Health Care Specifications Manual, issued by the Louisiana Department of Health and Hospitals, addresses the use of external cause codes, stating, “Diagnosis codes reported in the range of 800.00–999.99 (ICD-9) or S00.00xx–T88.99XXS (ICD-10) require the reporting of a valid External Cause-of-Injury Code.” According to the publication, while external cause codes are not valid as principal diagnosis codes, if the principal diagnosis code is trauma-related and there is no external cause code, then the record will be rejected.

    Experienced coders in medical coding companies can help physicians report external cause codes appropriately and based on their facility’s specific policy. Knowledgeable about payer and state public health department requirements as well as coding guidelines and conventions, they can help capture injury-related information to the highest level of specificity.