Clarification on the Use of External Cause and Unspecified Codes in ICD-10-CM

Approved by the four Cooperating Parties for ICD-10-CM/PCS and ICD-9-CM Coding, which includes American Health Information Management Association, American Hospital Association, Centers for Medicare & Medicaid Services, and National Center for Health Statistics

External Cause Codes

Just as with ICD-9-CM, there is no national requirement for mandatory ICD-10-CM external cause code reporting. Unless a provider is subject to a state-based external cause code reporting mandate or these codes are required by a particular payer, reporting of ICD-10-CM codes in Chapter 20, External Causes of Morbidity, is not required. If a provider has not been reporting ICD-9-CM external cause codes, the provider will not be required to report ICD-10-CM codes in Chapter 20, unless a new state or payer-based requirement regarding the reporting of these codes is instituted. Such a requirement would be independent of ICD-10-CM implementation. In the absence of a mandatory reporting requirement, providers are encouraged to voluntarily report external cause codes, as they provide valuable data for injury research and evaluation of injury prevention strategies.

Sign/Symptom/Unspecified Codes

In both ICD-9-CM and ICD-10-CM, sign/symptom and “unspecified” codes have acceptable, even necessary, uses. While specific diagnosis codes should be reported when they are supported by the available medical record documentation and clinical knowledge of the patient’s health condition, there are instances when signs/symptoms or unspecified codes are the best choices for accurately reflecting the healthcare encounter. Each healthcare encounter should be coded to the level of certainty known for that encounter.

If a definitive diagnosis has not been established by the end of the encounter, it is appropriate to report codes for sign(s) and/or symptom(s) in lieu of a definitive diagnosis. When sufficient clinical information isn’t known or available about a particular health condition to assign a more specific code, it is acceptable to report the appropriate “unspecified” code (e.g., a diagnosis of pneumonia has been determined, but not the specific type). In fact, unspecified codes should be reported when they are the codes that most accurately reflects what is known about the patient’s condition at the time of that particular encounter. It would be inappropriate to select a specific code that is not supported by the medical record documentation or conduct medically unnecessary diagnostic testing in order to determine a more specific code.


Source: Cooperating Parties for ICD-10-CM/PCS and ICD-9-CM Coding, May 2013.