Public health surveillance; ED data; asthma Data elements include disposition, initial vital signs, up to 11 ICD-9-CM final diagnosis codes, up to five external causes of injury codes (E-codes), as well as the arrival date and time, patient sex and age, patient zip and county and chief complaint. As of January 2008, NC DETECT emergency department data covered 99% of the NC population and captures approximately 4.5 million ED visits each year. As a result, requests for data from researchers continue to increase. Use of the data for public health purposes is covered by the mandate requiring hospitals to submit their emergency department data to NC DPH.