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ICD-10-CM External Cause Codes Tell the Whole Story

Use external cause codes to report in enhanced detail and possibly streamline claims submission and payment adjudication.

At some point in the near future, all claims for healthcare services in the United States will have to use ICD-10-CM diagnosis codes. ICD-9-CM has been the standard since 1979, but has outlived its usefulness. Because of its structure, ICD-10-CM provides better data for research and statistical analysis than ICD-9-CM. Although there is no national mandate to report them, external cause codes provide a unique opportunity to report significant detail not available in ICD-9-CM.

How, Why, When, Etc.

ICD-9-CM contains a lesser-known chapter entitled “Supplemental Classification of External Causes of Injury and Poisoning.” These codes are distinctive because, unlike most other ICD-9-CM codes, they are alphanumeric—that is, they start with the letter “E.” These codes permit the classification of environmental events, circumstances, and conditions as the cause of injury and other adverse effects, and are to be used in addition to codes that report the actual injury. For example:
E813.1 Motor vehicle traffic accident involving collision with other vehicle injuring passenger in motor vehicle other than motorcycle
Some providers already use these codes voluntarily or when required on auto insurance claims; however, many billers are unfamiliar with external cause codes. Unless a provider is subject to state-based mandates, or a specific payer requires them, you don’t need to report these codes. The Centers for Medicare & Medicaid Services (CMS) encourages you to do so, however, because they provide valuable data for injury research and evaluation of injury prevention strategies. They may also be helpful for determining liability in third-party injury claims.
It’s possible payers might not ask to review records as often after implementation, if they can find most of the information they need on the claim form via the diagnosis codes reported. For example, suppose a patient presents to the doctor’s office and the records reflect:

  • The patient had sprain injuries in the neck;
  • She was driving a car that struck a sports utility vehicle;
  • The driver side air bag was deployed;
  • She was texting while on a neighborhood street; and
  • The travel was for work.

All of this information can be reported with one injury code and several external cause codes in ICD-10.

External Cause Codes Are Versatile

External cause codes were extensively reworked for ICD-10-CM. The guidelines state that these codes are most often reported secondarily to codes from nearby chapter 19, Injury, poisoning, and certain other consequences of external causes (S00-T88). Chapter 19 codes begin with the letters S or T, and this is where codes for acute injuries are found, such as those sustained in an automobile accident.
In other words, if the physician were to select a code such as S13.4xxA Sprain of ligaments of cervical spine, initial encounter, it’s also appropriate to report the external cause of the injury. The S code would act as the primary diagnosis; external cause codes can never be reported first.
In ICD-10-CM, external cause codes are found in chapter 20, which includes codes that start with the letters V, W, X, and Y. Codes from V00 to V99 are separated into 12 groups, which reflect the patient’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. An example of a complete code that might be used in the case mentioned above is:
V43.51xA Car driver injured in collision with sport utility vehicle in traffic accident, initial encounter
The W codes are for injuries due to slipping, tripping, stumbling, and falling; the codes from W20 to W49 are categorized as “exposure to inanimate mechanical forces.” A code found in this section that fits our example case is:
W22.11xA Striking against or struck by driver side automobile airbag, initial encounter
The Y codes contain two important categories: Y92 for place of occurrence of the external cause and Y93, which is an activity code. The guidelines state these codes are to be used with one another, and are only reported on the initial encounter. Examples of place and activity codes a doctor might report in our example case are:
Y92.414 Local residential or business street as the place of occurrence of the external cause
Y93.C2 Activity, hand held interactive electronic device
There are also a few employment status codes in the Y99 category that could be assigned when Y93 (activity) codes are selected. They describe if the person is employed, in the military, a volunteer, or other status, and are reported only for the initial encounter. For example, if the victim was on the clock during the accident, the following code would indicate it may be related to worker’s compensation:
Y99.0 Civilian activity done for income or pay
Many payers require the submission of paper documentation to substantiate care. One reason ICD-10-CM was created was to minimize the need for a review of the doctor’s notes. If the codes are detailed enough and reported correctly, a record review would not add much more information. Payers would have nearly everything they need to know from the claim form alone. Our example case, for instance, includes one injury code from chapter 19, and five external cause codes from chapter 20.

Ensure a Happy Ending

External cause code reporting is voluntary (but is encouraged) when ICD-10-CM is implemented. It provides the opportunity to report enhanced detail, and could streamline the process of claims submission and payment adjudication. It may also improve the process of data collection for researchers and policy makers. Physicians and coders, however, must take the time to get familiar with coding guidelines and conventions to take advantage of this opportunity provided by ICD-10 .
Medicare Learning Network, ICN 902143, April 2013
Complete and Easy ICD-10-CM Coding for Chiropractic, 2nd edition, The ChiroCode Institute, 2013.
“ICD-10-CM. It’s closer than it seems,” CMS News Updates. May 17, 2013.
Evan M. Gwilliam, DC, MBA, CPC, CCPC, CPC-I, CCCPC, CPMA, NCICS, MCS-P, is the director of education for FindACode, and is the only chiropractic physician who is also an AAPC certified ICD-10-CM trainer. He spends most of his time teaching chiropractic physicians and other health professionals how to get ready for ICD-10-CM. If you are looking for a speaker or ICD-10-CM resources, he can be reached at Gwilliam is a member of the Provo, Utah, local chapter.

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Michelle A. Dick, BS, provides writing and editorial expertise to clients. She is a freelance proofreader for Partners & Napier’s Vine Creative Studios and the owner of My Garden Gal, a garden maintenance and landscaping business. Prior to becoming a free agent, Dick was an executive editor for AAPC.

6 Responses to “ICD-10-CM External Cause Codes Tell the Whole Story”

  1. Tiffany Carlson says:

    What would be the proper way to code no know injury? Are we still required to use external cause codes on those?

  2. Megan Scopley says:

    I am wondering the same thing. What code is used when the report says there was a car wreck but does not mention any injury? Sad to see it’s been over a year without an answer to the previous person’s question.

  3. Elizabeth Keffer says:

    Megan, I am working on an account right now that involves this exact scenario. Passenger in MVA but no injury. I plan to use Z041 as my principal with shoulder pain as a secondary dx. Since there was no injury found I plan to leave the e-codes off of this account. Am hoping this is correct. I would have also like to have seen a response to the original question from a year ago.

  4. janice C says:

    Looking for an answer as well for questions regarding an accident … (in this case a fall) that did not sustain any injuries. The documentation gives no diagnosis, only discusses the fall and the fact that the child suffered no injuries as a result of the fall. Any suggestions on proper way to code this. My thought is to submit documentation that the fall was the only i10 code that could be used. Thoughts?

  5. zinzi says:

    Looking for External code for S81.9. The patient had a cellulitis and it had lead to an abcess then now its an open wound. Which external code must i use.

  6. Dominique Hojda says:

    If there are no injuries in a car accident, I would code Z041 Encounter for examination and observation following transport accident.