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).
For the fourth quarter of 2015 and all of 2016, I10_NECause indicates the total number of external cause of morbidity codes (valid and invalid) that are included in the code array (I10_ECAUSEn).
For data prior to the fourth quarter of 2015, the count of the ICD-9-CM external cause of injury codes is stored in the data element NECODE.
In the HCUP State Databases all external cause of morbidity codes are retained on the record. In the NIS, only the first four external cause of morbidity codes are retained on the record and I10_NECause is set to a maximum of 4.