Beginning with the 2017 HCUP databases, International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) external cause of morbidity codes are included with other diagnoses in the diagnosis-related data elements (I10_DXn, I10_NDX, and DXPOAn) and are no longer retained in separate data elements (I10_ECAUSEn, I10_NECAUSE, and E_POAn).

From quarter four of 2015 and all of 2016, external cause of morbidity codes are stored in the data element I10_ECAUSEn. In data prior to the fourth quarter of 2015, International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) external cause of injury codes (E codes) are stored in the data element ECODEn.

In the HCUP databases, ICD-10-CM external cause of morbidity codes are represented by alphanumeric codes with a maximum length of 7 characters and implicit decimals (i.e., decimals not included). The HCUP data elements for these codes are length 7. The first digit is always character (V, W, X, and Y), the second digit is always numeric, and all subsequent digits can be character or numeric. The codes are left-justified in the HCUP databases. For example, the diagnosis code Y93.0 would appear as 'Y930 ' with trailing blanks in the HCUP data.

External cause of morbidity codes are compared to a list of ICD-10-CM codes valid for the discharge date. Anticipation of or lags in response to official ICD-10-CM coding changes are permitted for discharges occurring within a window of time (six months before and six months after) around the official ICD-10-CM coding changes (usually October 1). Invalid and inconsistent diagnoses are masked directly. Clinical Classifications Software (CCS) data elements are coded with respect to the external cause of morbidity codes.