HL7 SIU_S13 Appointment Rescheduling

The appointment still exists, but its scheduled time or timing pattern changed.
HL7 message structure SIU_S12 groups and segments from HL7 v2.5.1 Hide structure

These are the generated groups and segments for the version selected at the top of the page. The article explains the workflow, and this panel follows the chosen HL7 version.

Message Structure

SegmentNameRequiredRepeatable
MSH
 Message Header Yes No
SCH
 Scheduling Activity Information Yes No
TQ1
 Timing/Quantity No Yes
NTE
 Notes and Comments No Yes
SIU_S12.PATIENT
 Patient group No Yes
PID
 Patient Identification Yes No
PD1
 Patient Additional Demographic No No
PV1
 Patient Visit No No
PV2
 Patient Visit - Additional Information No No
OBX
 Observation/Result No Yes
DG1
 Diagnosis No Yes
SIU_S12.RESOURCES
 Resources group Yes Yes
RGS
 Resource Group Yes No
SIU_S12.SERVICE
 Service group No Yes
AIS
 Appointment Information Yes No
NTE
 Notes and Comments No Yes
SIU_S12.GENERAL_RESOURCE
 General Resource group No Yes
AIG
 Appointment Information - General Resource Yes No
NTE
 Notes and Comments No Yes
SIU_S12.LOCATION_RESOURCE
 Location Resource group No Yes
AIL
 Appointment Information - Location Resource Yes No
NTE
 Notes and Comments No Yes
SIU_S12.PERSONNEL_RESOURCE
 Personnel Resource group No Yes
AIP
 Appointment Information - Personnel Resource Yes No
NTE
 Notes and Comments No Yes

SIU_S13 is the unsolicited notification that an existing appointment has been rescheduled. The filler schedule already knows the appointment, and it is telling downstream systems to move that appointment rather than create a new one.

Like the other SIU notification events, S13 uses the shared SIU^S13^SIU_S12 structure. The trigger event says this is a reschedule; the SIU_S12 structure supplies the common scheduling layout shown in the panel below.

A small SIU S13 example

MSH|^~\&|SCHED|CITYHOSP|EHR|CITYHOSP|20260716130000||SIU^S13^SIU_S12|SIU130042|P|2.5.1 SCH|A100045|F100045||ROUTINE^Routine appointment^L|RESCHEDULED|OFFICE^Office visit^L|30|min|^^^20260719113000^20260719120000|||||12345^Careful^Clara PID|1||123456^^^CITYHOSP^MR||Smith^Jane^Anne^^Ms^^L||19800314|F|||12 High Street^^Auckland^^1010^NZ^H PV1|1|O|CARD^ROOM2^^CITYHOSP RGS|1 AIS|1||CARDREV^Cardiology review^L|20260719113000|30|min AIL|1||CARD^ROOM2^^CITYHOSP|20260719113000|30|min AIP|1||12345^Careful^Clara|CARD^Cardiologist^L|20260719113000|30|min

What systems do with it

The sender is the scheduling or filler application. Receivers move the appointment on calendars, worklists, reminders, preparation queues, resource schedules, and patient-facing systems. The key is preserving the appointment identity in SCH so the receiver updates the existing appointment instead of creating a duplicate.

The patient group still matters because receivers often use PID and PV1 to confirm the appointment belongs to the right patient and visit. Resource groups in RGS, AIS, AIL, and AIP tell the receiver which service, room, equipment, and people moved with the appointment.

How to read the structure

The generated panel shows SIU_S12 because all these SIU notification events share the same local structure. For S13, pay special attention to appointment identifiers in SCH and start/duration data in SCH, TQ1, AIS, AIL, and AIP.

If several timing fields are present, the interface specification should define which segment is authoritative. Otherwise one receiver may move the appointment to the SCH time while another follows the resource time.

Implementation traps

The classic trap is creating a second appointment. If the receiver cannot match the placer or filler appointment ID, it should reject or quarantine the message rather than quietly making a duplicate.

Another trap is using S13 for appointments that are already in progress or completed. HL7 scheduling guidance generally treats in-progress or completed appointments differently because changing their scheduled time creates ambiguity for downstream systems.

Reference notes

Caristix describes S13 as notifying other applications that an existing appointment has been rescheduled. HL7 Chapter 10 scheduling separates rescheduling from modification, cancellation, discontinuation, and deletion. iNTERFACEWARE's SIU overview also notes that SIU events share the same message format.