ICD-10 External Cause Codes Tell the Whole Story

by  ChiroCode
August 10th, 2015

Beginning October 1, 2015 all claims for health care services in the United States must use ICD-10 diagnosis codes. ICD-9 has been the standard since 1979, but has outlived its usefulness. Because of its structure, ICD-10 provides better data for research and statistical analysis than ICD-9. 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.

The How, Why, When...and More

ICD-9 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 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. 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 is possible that payers might not ask to review records as often, after October 1, if they can find most of the information they need on the claim form, via the diagnosis codes reported. For example, suppose that a patient presents to the doctor’s office, and the records reflect:

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. 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. 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 the neck, it is also appropriate to report the external cause of the injury. The “S code” would act as the primary diagnosis; whereas, external cause codes can never be reported first.

In ICD-10, 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 in to 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 earlier 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 falls; the codes from W20 to W49 are categorized as “exposure to inanimate mechanical forces.” A code found in this section that fits this scenario is:

W22.11xA Striking against or struck by driver side automobile airbag 

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 that these codes are to be used with one another, and are only reported on the initial encounter. Examples of place and activity codes that a doctor might report in this case are:

Y92.414 Local residential or business street as the place of occurrence of the external cause

Y93.C2 Use of cellular telephone and other electronic equipment at the time of the transport accident

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 that it may be related to workers’ compensation:

Y99.0 Civilian activity done for income or pay

However, because workers compensation plans are not required to switch to ICD-10, not all plans are making the switch right now. Be aware of individual payer policies.

Many payers require the submission of paper documentation to substantiate care. One reason ICD-10 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. This example, for instance, includes one injury code from chapter 19, and five external cause codes from chapter 20.

Sweat the Details

External cause code reporting is voluntary (but is encouraged) once ICD-10 is implemented in October. 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. However, physicians and coders must take the time to get familiar with coding guidelines and conventions to take advantage of this opportunity provided by ICD-10.



Dr. Evan Gwilliam has an MBA and multiple certifications in coding, compliance, and auditing. He is the Director of Education and Consulting for the ChiroCode Institute, and is the only chiropractic physician who is also an AAPC Certified ICD-10 Trainer. He spends most of his time teaching chiropractic physicians and other health professionals how to get ready for ICD-10.

He can be reached via email at: DrG@ChiroCode.com.

ICD-10 External Cause Codes Tell the Whole Story. (2015, August 10). Find-A-Code Articles. Retrieved from https://www.findacode.com/articles/icd-10-external-cause-codes-tell-the-whole-story-vol-20-no1-qtr1-1786.html

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