SIU^S12 — Notification of New Appointment Booking

The message that notifies the creation of a new patient appointment. Broadcast to the EHR, the practitioner agenda, the billing module and the patient portal.

Purpose of the message

SIU^S12 is broadcast when a scheduling system creates a new patient appointment. It carries everything consumer systems need:

• appointment identifier (stable reference key for future SIU^S13, S14, S15…);
• appointment type (consult, exam, intervention);
• time slot (start, end, duration);
• concerned patient (PID);
• service resource (AIS);
• equipment (AIG);
• location (AIL — room, floor, building);
• personnel / practitioner (AIP).

The message is consumed by: the EHR to preload the patient record before arrival, the patient portal to confirm the appointment, the billing module to pre-create the service line, the SMS / e-mail reminder module, the practice dashboard.

Segment structure

SIU_S12
  MSH                    Message Header (mandatory)
  SCH                    Scheduling Activity Information (mandatory)
  [ { NTE } ]
  [ { PATIENT
      PID                Patient Identification
      [ PD1 ]
      [ PV1 ]            Patient Visit
      [ PV2 ]
      [ { OBX } ]
      [ { DG1 } ]
    } ]
  { RESOURCES
      RGS                Resource Group (mandatory in group)
      [ { SERVICE
          AIS            Appointment Information - Service
          [ { NTE } ]
        } ]
      [ { GENERAL_RESOURCE
          AIG            Appointment Information - General Resource
          [ { NTE } ]
        } ]
      [ { LOCATION_RESOURCE
          AIL            Appointment Information - Location Resource
          [ { NTE } ]
        } ]
      [ { PERSONNEL_RESOURCE
          AIP            Appointment Information - Personnel Resource
          [ { NTE } ]
        } ]
    }

MSH — Message Header

• MSH-9: SIU^S12^SIU_S12.
• MSH-10: unique message identifier.
• MSH-12: 2.5.1.

SCH — Scheduling Activity Information

The central SIU segment. Key fields:

• SCH-1: Placer Appointment ID (identifier from the system creating the appointment).
• SCH-2: Filler Appointment ID (identifier from the system managing the appointment; for external booking via Doctolib, differs from SCH-1).
• SCH-3: Occurrence Number (for recurring appointments).
• SCH-6: Schedule Reason.
• SCH-7: Appointment Reason (CE) — appointment type per local table.
• SCH-8: Appointment Type (table 0276: ROUTINE, WALKIN, CHECKUP, FOLLOWUP, EMERGENCY).
• SCH-9: Appointment Duration.
• SCH-10: Duration Units.
• SCH-11: Appointment Timing Quantity (TQ) — the time slot.
• SCH-20: Entered By Person (XCN).
• SCH-25: Filler Status Code (table 0278: Booked, Pending, Cancelled, Complete, Noshow).

PID — PV1

Patient identity (PID, see ADT^A01) and, for scheduled outpatient appointments, the associated visit (PV1).

RGS — AIS / AIG / AIL / AIP

The Resources group describes every resource booked by the appointment:

• RGS — start of resources group. RGS-1 = sequence number, RGS-2 = action code (A = Add, M = Modify, D = Delete).
• AIS (Appointment Information — Service) — requested service / procedure. AIS-3 = CCAM / CPT code.
• AIG (Appointment Information — General Resource) — equipment (ECG, ultrasound, MRI machine…).
• AIL (Appointment Information — Location Resource) — location (room, floor, building, facility).
• AIP (Appointment Information — Personnel Resource) — involved personnel (physician, nurse).

Real example

Creation of a 30-minute cardiology consult for John Doe with Dr Jones on 20 May 2026 at 09:30, in room CARDIO-101, with EKG 1 reserved:

MSH|^~\&|SCHED|HOSP01|EHR|HOSP01|20260514110000||SIU^S12^SIU_S12|MSG00007890|P|2.5.1
SCH|APP2026-001||APPT2026-001||1^Routine||CONS^Consultation||30|min|^^^20260520093000^20260520100000|||||DRJONES^Jones^Sarah^^^DR.|+33142000000^^WORK||||DRJONES^Jones^Sarah^^^DR.|||||Booked
PID|1||MRN567890^^^HOSP^MR||DOE^JOHN^A^^MR.||19720515|M||||100 MAIN ST^^ANYTOWN^CA^90210^USA||(555)555-1234|||S||ACCT123456
PV1|1|O|CARDIO^^^HOSP01|||||DRJONES^Jones^Sarah^^^DR.|||||||||VIP||||||||||||||||||||HOSP01
RGS|1|A
AIS|1|A|99213^Office visit, level 3^CPT||20260520093000|||||1800
AIG|1|A|EKG001^EKG Machine 1^DEVICE
AIL|1|A|CARDIO-101^^Cardiology Room 101^Cardiology Floor^^HOSP01
AIP|1|A|DRJONES^Jones^Sarah^^^DR.|RP^Responsible Provider^HL70443|20260520093000

• SCH — consult appointment APPT2026-001, 30 min, slot 09:30-10:00 on 20 May 2026, physician Jones, status Booked.
• PID — patient John Doe, MRN 567890.
• PV1 — outpatient in Cardiology.
• AIS — Office visit CPT 99213, duration 1800 seconds.
• AIG — EKG1 equipment reserved.
• AIL — room CARDIO-101.
• AIP — Dr Jones as Responsible Provider.

Acknowledgement

The receiving EHR acknowledges with ACK^S12:

MSH|^~\&|EHR|HOSP01|SCHED|HOSP01|20260514110001||ACK^S12^ACK|ACK00007890|P|2.5.1
MSA|AA|MSG00007890

Common errors

• Inconsistent SCH-1 / SCH-2 — Placer and Filler appointment IDs must identify the originating and executing agendas. Swapping them breaks reconciliation.
• Ambiguous TQ time slot — use a complete TQ format ^^^DTSTART^DTEND. A bare 20260520093000^20260520100000 without prefix is interpreted variably.
• Missing AIP — an appointment without a recorded practitioner breaks physician scheduling and reminders.
• AIL pointing to unknown room — the room identifier in AIL-3 must match an existing location in the HIS; otherwise IT operations gets the alert.
• Missing SCH-25 — without Filler Status Code, the receiver doesn't know if the appointment is Booked, Pending or other. Always set Booked for S12.
• Recurring appointment without Occurrence Number — for periodic appointments (physio 2x/week), SCH-3 must increment per occurrence to allow individual cancellation.

Related SIU events

FHIR equivalent

In FHIR R5, SIU^S12 maps to the Appointment resource with status=booked. Mappings:

• SCH-1/2 → Appointment.identifier (placer + filler)
• SCH-11 → Appointment.start / Appointment.end
• SCH-25 → Appointment.status
• SCH-7 → Appointment.serviceCategory / serviceType / appointmentType
• PID → Appointment.participant (Patient)
• AIP → Appointment.participant (Practitioner)
• AIL → Appointment.participant (Location)
• AIG → Appointment.participant (Device)

Creating a FHIR Appointment is followed by an AppointmentResponse workflow for each participant (confirmation, refusal). No-show is captured as status=noshow.