HOSP_ED is a HCUP hospital identifier created specifically for the Nationwide Emergency Department Sample (NEDS). Its purpose is to identify ED records that are associated with the same hospital-based ED. HOSP_ED does not link to other HCUP databases or to external databases. In contrast to the HCUP hospital identifier HOSPID, HOSP_ED does not identify the state of the hospital, only the region of the U.S.

For consistency across states, HCUP defines hospital-based EDs in accordance with the American Hospital Association Annual Survey of Hospitals. During HCUP data processing, the data source's identification of the hospital is reconciled with the identification of the hospital in the AHA Annual Survey. For detailed information about this linking process, see the special report on HCUP Hospital Identifiers.