EVN - Event Type Segment

The EVN segment is used to communicate necessary trigger event information to receiving applications. Valid event types for all chapters are contained in HL7 Table 0003 - Event Type.

HL7 Attribute Table - EVN - Event Type Segment

Seq#	Data Element Name	DataType	Usage	Vocabulary	Cardinality	Item #	Length	C.LEN	Flags
EVN
1	Event Type Code		W		[0..1]	00099
2	Recorded Date/Time	DTM	R		[1..1]	00100
3	Date/Time Planned Event	DTM	O		[0..1]	00101
4	Event Reason Code	CWE	O	0062 Event Reason	[0..1]	00102
5	Operator ID	XCN	O	0188 Operator ID	[0..*]	00103
6	Event Occurred	DTM	O		[0..1]	01278
7	Event Facility	HD	O		[0..1]	01534

EVN-1: Event Type Code () 00099

Attention: The EVN-1 field was retained for backward compatibilty only as of v2.5 and the detail was withdrawn and removed from the standard as of v2.7.

EVN-2: Recorded Date/Time (DTM) 00100

Definition: Most systems will default to the system date/time when the transaction was entered, but they should also permit an override.

EVN-3: Date/Time Planned Event (DTM) 00101

Definition: This field contains the date/time that the event is planned. We recommend that PV2-8 - Expected Admit Date/Time, PV2-9 - Expected Discharge Date/Time or PV2-47 - Expected LOA Return date/time be used whenever possible.

EVN-4: Event Reason Code (CWE) 00102

Definition: This field contains the reason for this event. Refer to User-defined Table 0062 - Event Reason in Chapter 2C, Code Tables, for suggested values.

EVN-5: Operator ID (XCN) 00103

Definition: This field identifies the individual responsible for triggering the event. Refer to User-defined Table 0188 - Operator ID in Chapter 2C, Code Tables, for suggested values.

EVN-6: Event Occurred (DTM) 01278

Definition: This field contains the date/time that the event actually occurred. For example, on a transfer (A02 transfer a patient), this field would contain the date/time the patient was actually transferred. On a cancellation event, this field should contain the date/time that the event being cancelled occurred.

EVN-7: Event Facility (HD) 01534

Definition: This field identifies the actual facility where the event occurred as differentiated from the sending facility (MSH-4). It would be the facility at which the Operator (EVN-5) has entered the event.

Use Case: System A is where the patient is originally registered. This registration message is sent to an MPI, System B. The MPI needs to broadcast the event of this update and would become the sending facility. This new field would allow for retention of knowledge of the originating facility where the event occurred. The MPI could be the assigning authority for the ID number as well which means that it is performing the function of assigning authority for the facility originating the event.