Patient Identification

HIEBus incorporates patient data from multiple data sources. Each human being may have data in multiple systems using different identifiers and potentially differing demographics. Each system’s view of each patient is incorporated into HIEBus as a distinct patient record in order to maintain provenance of the data. Patient records are identified by the combination of a record authority and an identifier (e.g. MRN).

One of the obvious foundations of a correct interface is that it creates the correct set of patient records and correctly assigns data appropriately to those patient records. In HIEBus the identification of a patient record is done with the combination of a record authority and a patient identifier.

Record Authority

The record authority is what HIEBus uses to scope identifiers. It is like HL7’s assigning authority or FHIR’s identifier.System. An identifier will be unique within a given record authority, but an identifier may exist in multiple record authorities and may represent different entities in each record authority.

There are two modes for determining the record authority for a patient:

1. Fixed. If the primary patient identifier in the interface is from a single source of patient identifiers—i.e., a single registration system—then the record authority will be fixed for the interface when the interface is configured.
2. Message basis. If the interface contains patients with primary identifiers assigned by multiple identifier pools—i.e., the interface aggregates data from multiple registration systems—then the record authority can be identified by data in the message. The most common field for conveying this information is MSH 4 (Sending Facility). Because MSH 4 is often used also to identify the default term namespace, when the default term namespace and patient record authority are not the same, another field may be chosen, such as MSH 3 (Sending Application). PID-3.4 (Patient Identifier Assigning Authority) may also be used, but when there are multiple patients in a message, all patients in a single message must use the same patient record authority.

Patient Identifier

HIEBus requires that the patient record identifier be supplied as the first repetition of PID 3.

The first repetition of PID 3 will be used as the patient record’s patient identifier. All repetitions of PID 3, including the first, will generate identifiers attached to the patient’s demographic record, but subsequent repetitions are not used in primary record identification.

Examples

The following examples are based on the following message:

MSH|^~\&|HL7REG|UH|HL7LAB|CH|200102280700||ADT^A08^ADT_A08|MSGID002|P|2.7|||AL|NE
PID|1||PATID1234^5^M11^ADT1^MR^GOOD HEALTH HOSPITAL~123456789^^^USSSA^SS||EVERYMAN^ADAM^A^III||19610615|M||2106-3|2222 HOME STREET^^GREENSBORO^NC^27401-1020|||||||ENC1234
PV1|1|I|2000^2012^01||||004777^ATTEND^AARON^A|||SUR||||7|A0|

Fixed record authority

For a driver set up with a fixed patient record authority of “UNIVERSITY HOSPITAL”:

Record Authority Determined By MSH-4

Record Authority Determined By PID-3.4