HL7 SCH Segment: Scheduling Activity Information

The SCH segment carries the scheduling-level detail of an appointment: the placer and filler appointment IDs, the reason the schedule event occurred, the appointment type and duration, the timing quantity, and the people involved in placing, filling, and entering the booking. It is the spine of an SIU message — where the message header says what scheduling event happened, SCH says which appointment it is, when it runs, and who owns it.

Purpose

SCH describes a single scheduling activity: identifiers that tie the placer and filler systems together, the event reason and appointment reason/type, the requested duration and timing, contact people on both the placer and filler sides, the entering user, and the filler status that drives the appointment's lifecycle. Fields are populated differently per trigger event — a new booking (S12) fills the timing and contacts, while a status change updates SCH-25.

Used in

SCH appears in SIU scheduling messages — new appointment (S12), reschedule (S13), modify (S14), cancel (S15), discontinue (S16), delete (S17), and the other scheduling triggers. It anchors the appointment that the resource group (RGS) and resource segments (AIG, AIL, AIP, AIS) hang beneath. See SIU.

Field-by-field reference

Source: the Vorro HL7 segment database (extracted from the official v2-to-FHIR IG). R = required (cardinality min ≥ 1). Repeat = field may repeat. Length is not carried by the FHIR source and is shown as —.

Seq	Name	Data Type	Length	Req	Repeat	Table #	Description
SCH-1	Placer Appointment ID	EI	—	O	—	—	Placer system's appointment identifier.
SCH-2	Filler Appointment ID	EI	—	O	—	—	Filler system's appointment identifier.
SCH-3	Occurrence Number	NM	—	O	—	—	Occurrence within a repeating appointment series.
SCH-4	Placer Group Number	EI	—	O	—	—	Groups related placer appointments together.
SCH-5	Schedule ID	CWE	—	O	—	—	Identifier of the schedule being booked against.
SCH-6	Event Reason	CWE	—	R	—	—	Why this scheduling event occurred. Required.
SCH-7	Appointment Reason	CWE	—	O	—	—	Clinical reason for the appointment.
SCH-8	Appointment Type	CWE	—	O	—	—	Kind of appointment (routine, walk-in, etc.).
SCH-9	Appointment Duration	NM	—	O	Y	—	Requested length of the appointment.
SCH-10	Appointment Duration Units	CNE	—	O	Y	—	Units for the duration value.
SCH-11	Appointment Timing Quantity	TQ	—	R	Y	—	Start time and timing of the appointment. Required.
SCH-12	Placer Contact Person	XCN	—	R	Y	—	Person on the placer side to contact. Required.
SCH-13	Placer Contact Phone Number	XTN	—	O	—	—	Phone number for the placer contact.
SCH-14	Placer Contact Address	XAD	—	O	Y	—	Address for the placer contact.
SCH-15	Placer Contact Location	PL	—	O	—	—	Location of the placer contact.
SCH-16	Filler Contact Person	XCN	—	R	Y	—	Person on the filler side to contact. Required.
SCH-17	Filler Contact Phone Number	XTN	—	O	—	—	Phone number for the filler contact.
SCH-18	Filler Contact Address	XAD	—	O	Y	—	Address for the filler contact.
SCH-19	Filler Contact Location	PL	—	O	—	—	Location of the filler contact.
SCH-20	Entered By Person	XCN	—	R	Y	—	User who entered the scheduling request. Required.
SCH-21	Entered By Phone Number	XTN	—	O	Y	—	Phone number for the entering user.
SCH-22	Entered By Location	PL	—	O	—	—	Location of the entering user.
SCH-23	Parent Placer Appointment ID	EI	—	O	—	—	Placer ID of a parent appointment.
SCH-24	Parent Filler Appointment ID	EI	—	O	—	—	Filler ID of a parent appointment.
SCH-25	Filler Status Code	CWE	—	O	—	—	Current status of the appointment. Drives lifecycle.
SCH-26	Placer Order Number	EI	—	O	Y	—	Order(s) the appointment is based on.
SCH-27	Filler Order Number	EI	—	O	Y	—	Filler order number(s) for the appointment.

Most-used fields

SCH-6 Event Reason is one of the required fields and explains why the scheduling event fired; it also drives the FHIR ServiceRequest intent.
SCH-11 Appointment Timing Quantity carries the appointment start and timing — the field most downstream calendar and reminder logic reads.
SCH-25 Filler Status Code is the lifecycle switch: it maps to the FHIR Appointment.status and tells receivers whether the slot is booked, cancelled, or completed.
SCH-1 Placer Appointment ID and SCH-2 Filler Appointment ID are the identifiers systems match on to tie placer and filler views of the same appointment.
SCH-12 Placer Contact Person, SCH-16 Filler Contact Person, and SCH-20 Entered By Person are the three required people and become Appointment participants and Provenance agents.

Version differences (2.3 to 2.8.2)

2.3: SCH introduced with the scheduling chapter; SCH-1 through SCH-25 defined.
2.4/2.5: SCH-26 Placer Order Number and SCH-27 Filler Order Number added to link appointments to orders.
2.5: coded fields move from CE toward CWE; timing increasingly expressed through SCH-11 rather than legacy quantity/timing pairs.
2.7+: timing-quantity usage refined as TQ is deprecated in favor of TQ1/TQ2 segments in newer messages; receivers built for 2.3 ignore trailing fields they do not recognize.

Common mistakes

Omitting SCH-6 or SCH-11 — both are required, and many engines reject the segment when they are missing.
Reading only the first repetition of SCH-12/SCH-16/SCH-20 when several contacts are listed.
Treating SCH-25 as cosmetic and not mapping it to Appointment.status, so cancellations never propagate.
Confusing the placer (SCH-1) and filler (SCH-2) appointment IDs and matching on the wrong side.

Examples

Minimal valid SCH (required fields only — event reason, timing, the three contacts):

SCH|||||| ROUTINE|||||^^^20260615090000|1234^SMITH^JANE^A^^^MD||||5678^JONES^MARK^B^^^MD||||9012^CLERK^PAT

Fully-populated SCH (new appointment booking):

SCH|APPT-1001^MERCYGEN|FILL-2002^MERCYGEN|1|GRP-300^MERCYGEN|SCHED-CARDIO|ROUTINE^Routine|FOLLOWUP^Follow-up|OFFICE^Office Visit|30|MIN^Minutes|^^^20260615090000^20260615093000|1234^SMITH^JANE^A^^^MD|^^^^^555^5550100|123 MAIN ST^^METROCITY^ST^00000||5678^JONES^MARK^B^^^MD|^^^^^555^5550200|456 OAK AVE^^METROCITY^ST^00000||9012^CLERK^PAT|^^^^^555^5550300||||||BOOKED|ORD-700^MERCYGEN|ORD-800^MERCYGEN

Annotated breakdown of the fully-populated example (selected fields):

SCH                              ← segment ID
APPT-1001^MERCYGEN               ← SCH-1  Placer Appointment ID
FILL-2002^MERCYGEN               ← SCH-2  Filler Appointment ID
ROUTINE^Routine                  ← SCH-6  Event Reason (required)
OFFICE^Office Visit              ← SCH-8  Appointment Type
30                               ← SCH-9  Appointment Duration
^^^20260615090000^20260615093000 ← SCH-11 Appointment Timing Quantity (required)
1234^SMITH^JANE^A^^^MD           ← SCH-12 Placer Contact Person (required)
5678^JONES^MARK^B^^^MD           ← SCH-16 Filler Contact Person (required)
9012^CLERK^PAT                   ← SCH-20 Entered By Person (required)
BOOKED                           ← SCH-25 Filler Status Code
ORD-700^MERCYGEN                 ← SCH-26 Placer Order Number

In-context inside an SIU^S12 (new appointment booking):

MSH|^~&|SCHED|MERCYGEN|EHR|MERCYGEN|20260610120000||SIU^S12^SIU_S12|MSG2001|P|2.5.1
SCH|APPT-1001^MERCYGEN|FILL-2002^MERCYGEN|||SCHED-CARDIO|ROUTINE^Routine||OFFICE^Office Visit|30|MIN^Minutes|^^^20260615090000^20260615093000|1234^SMITH^JANE^A^^^MD||||5678^JONES^MARK^B^^^MD||||9012^CLERK^PAT|||||||BOOKED
PID|1||MR12345^^^MERCYGEN^MR||DOE^JOHN^Q||19800101|M
RGS|1|A
AIG|1|A|CARDIO^Cardiology|||||20260615090000|||30|MIN

In-context inside an SIU^S12 with a resource and location group:

MSH|^~&|SCHED|MERCYGEN|EHR|MERCYGEN|20260610120500||SIU^S12^SIU_S12|MSG2002|P|2.5.1
SCH|APPT-1003^MERCYGEN|FILL-2004^MERCYGEN|||SCHED-DERM|ROUTINE^Routine||CONSULT^Consult|45|MIN^Minutes|^^^20260616103000^20260616111500|2233^BAKER^LISA^^^^MD||||3344^FORD^ANNA^^^^MD||||9012^CLERK^PAT|||||||BOOKED|ORD-701^MERCYGEN
PID|1||MR67890^^^MERCYGEN^MR||ROE^MARY^A||19751212|F
RGS|1|A
AIL|1|A|CLINIC-2^Room 2^MERCYGEN|||20260616103000|||45|MIN
AIP|1|A|2233^BAKER^LISA^^^^MD|D^Dermatologist||20260616103000|||45|MIN

FHIR mapping

Primary target resource: Appointment. SCH also drives a ServiceRequest (SCH-6 sets intent, SCH-26/27 become identifiers, and the segment seeds status active) and a Provenance resource (SCH-20 becomes the entering agent). Official ConceptMaps: Appointment, Provenance, ServiceRequest.

Key Appointment mappings:

SCH field	FHIR target (Appointment)
SCH-1 Placer Appointment ID	`Appointment.identifier[1]`
SCH-2 Filler Appointment ID	`Appointment.identifier[2]`
SCH-7 Appointment Reason	`Appointment.reasonCode[1]` (also `appointmentType`)
SCH-8 Appointment Type	`Appointment.appointmentType`
SCH-9 Appointment Duration	`Appointment.minutesDuration`
SCH-11 Appointment Timing Quantity	`Appointment` timing (`TQ[Appointment]`)
SCH-12 Placer Contact Person	`Appointment.participant[1].actor` (Practitioner, placer contact)
SCH-16 Filler Contact Person	`Appointment.participant[2].actor` (Practitioner, filler contact)
SCH-20 Entered By Person	`Appointment.participant[3].actor` (Practitioner, enterer)
SCH-25 Filler Status Code	`Appointment.status`
SCH-26 Placer Order Number	`Appointment.basedOn` (ServiceRequest)
SCH-27 Filler Order Number	`Appointment.basedOn` (ServiceRequest)

Other targets: SCH-20 Entered By Person → Provenance.agent[1].who (type enterer); SCH-6 Event Reason → ServiceRequest.intent (order), with SCH-26/27 as ServiceRequest.identifier and SCH-25 carried into ServiceRequest.status. Fields without a published Appointment mapping (SCH-3, SCH-4, SCH-5, SCH-6, SCH-10, SCH-13 through SCH-15, SCH-17 through SCH-19, SCH-21 through SCH-24) are scheduling/contact details not represented directly on Appointment.

Engine considerations

Required in practice: SCH-6 (event reason) and SCH-11 (timing) are standard-required, and real interfaces also depend on SCH-1/SCH-2 (identifiers) and SCH-25 (status) for matching and lifecycle.
Parse SCH-11 carefully so the appointment start and end survive into Appointment timing.
Map SCH-25 to Appointment.status so cancellations and completions propagate, not just new bookings.
Repeating people fields (SCH-12/16/20/21) and contact-address fields (SCH-14/18) must be preserved as arrays.

How Vorro parses and produces SCH

Vorro indexes SCH-1 and SCH-2 as the placer/filler appointment keys so updates attach to the correct booking, maps SCH-25 to the FHIR Appointment.status, and decomposes SCH-11 into the appointment start/end. The three required people (SCH-12, SCH-16, SCH-20) are emitted as typed Appointment.participant actors per the official ConceptMap, and SCH-20 additionally produces a Provenance agent. When order numbers are present, Vorro links SCH-26/27 to ServiceRequest via basedOn.

AIG — the appointment resource (general) the SCH appointment uses.
RGS — the resource group the appointment's resources are organized under.
SIU messages — where SCH drives book, reschedule, modify, and cancel.

Sources

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