Why Isn't "Dog Bite" a Valid Diagnosis Code? Diagnosis Coding Rules Explained

Reduce your claim denials with improved diagnosis coding"She was bitten by a dog.  How much clearer can I be?”

"He fell.  That’s what I wrote on the encounter form.  He fell.”

When it comes to injuries, it often seems that physicians and coders are speaking in different languages.  Physicians are speaking in English and coders are speaking in—well—code.  Why aren’t “dog bite” or “fall” sufficient diagnosis codes?

Diagnosis coding rules require that when medical practices submit a claim for an injury, the injury itself (laceration, contusion, fracture, sprain) be listed first and the cause of the injury (dog bite, fall) be listed second.  These causes, called “external causes” in ICD-9, begin with the letter E.  E codes may never be used in the first position on the claim form.  Use the physical injury first and the cause second.

The E codes are located after the V codes in the ICD-9 book and are titled, “Supplementary Classification of External Causes of Injury and Poisoning (E000-E999).”  According to the Official Guidelines, E codes are used to describe the activity of a person seeking care at the time of the accident, as well as other health conditions related to the injury.   The introduction in the Guidelines state, “E codes capture how the injury, poisoning, or adverse effect happened (cause), the intent (unintentional or accidental; or intentional, such as suicide or assault), the person’s status (e.g. civilian, military), the associated activity, and the place where the event occurred.”

In ICD-9, E codes may be used with any code in the range 001-V91.  The coder is instructed to use as many E codes as is necessary to describe the cause, intent and place of occurrence.   They may never be a principal diagnosis, so the result of writing simply “dog bite” or “fall” will be that the claim is denied.  As more providers are selecting their own ICD-9 codes in their Electronic Health Records, it is important that they understand the correct use of E codes, and that the software have an edit that will stop the claim before submission if the E code is used alone, or is first.

What if an injury ICD-9 code is submitted without a cause? That is, “contusion” without “fall”? Most payers will deny or suspend the claim, and ask for more information.  What if “fall” is submitted without “contusion”? The denial reason will be something like this: “Principal diagnosis: invalid; must not be an external cause of injury code.” Correctly submitting the diagnosis codes when the claim is submitted the first time can speed payments and prevent the need to handle the claim a second time.  These codes are frequently used in emergency departments and urgent care centers, but are also used for visits to patients in nursing homes and in primary care offices, orthopedics and for chiropractic services.

ICD-10 will require this same format
Although the timeline for ICD-10 implementation is in question, when medical practices do adopt it, coding for injuries will require this same format in addition to seventh digit extenders for injury codes.  This seventh digit will indicate whether it was the initial encounter for this injury, a subsequent encounter or a long term after-effect.  In addition, the practice will need to report the external cause of the injury at every visit for that condition. The first time the clinician sees the patient for that injury, the practice will need to report three additional occurrence cause codes.  These external cause codes will indicate the place of occurrence, the activity the patient was engaged in and identify the patient (military, civilian, etc).

For now, medical groups that treat injuries should review the use of E codes by reading the guidelines related to the codes and reminding clinicians that they are never listed in the first place on an encounter form.

About the Author

Betsy Nicoletti is the author of The Field Guide to Physician Coding and founder of Codapedia.com. She developed The Accurate Coding System to help doctors get paid....

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