In computing, an enterprise[-wide] master patient index is a form of customer data integration (CDI) specific to the healthcare industry. Healthcare organizations and groups use EMPI to identify, match, merge, de-duplicate, and cleanse patient records to create a master index that may be used to obtain a complete and single view of a patient. The EMPI will create a unique identifier for each patient and maintain a mapping to the identifiers used in each records' respective system.An EMPI will typically provide an application programming interface (API) for searching and querying the index to find patients and the pointers to their identifiers and records in the respective systems. It may also store some subset of the attributes for the patient so that it may be queried as an authoritative source of the "single most accurate record" or "source of truth" for the patient. Registration or other practice management applications may interact with the index when admitting new patients to have the single best record from the start, or may have the records indexed at a later time.