HL7 AIL Appointment Information - Location Resource
HL7 field reference AIL fields from HL7 v2.5.1 Show fields
These are the generated fields for the version selected at the top of the page. The document stays the same, but the reference panel follows that version.
Fields
| Field | Name | Required | Repeatable | Type | Table |
|---|---|---|---|---|---|
| AIL.1 | Set ID - AIL | Yes | No | SI | |
| AIL.2 | Segment Action Code | No | No | ID | 0206 |
| AIL.3 | Location Resource ID | No | Yes | PL | |
| AIL.4 | Location Type-AIL | No | No | CE | 0305 |
| AIL.5 | Location Group | No | No | CE | |
| AIL.6 | Start Date/Time | No | No | TS | |
| AIL.7 | Start Date/Time Offset | No | No | NM | |
| AIL.8 | Start Date/Time Offset Units | No | No | CE | |
| AIL.9 | Duration | No | No | NM | |
| AIL.10 | Duration Units | No | No | CE | |
| AIL.11 | Allow Substitution Code | No | No | IS | 0279 |
| AIL.12 | Filler Status Code | No | No | CE | 0278 |
AIL is the HL7 Appointment Information - Location Resource segment. The AIL segment contains information about location resources (meeting rooms, operating rooms, examination rooms, or other locations) that can be scheduled. Resources included in a transaction using this segment are assumed to be controlled by a schedule on a schedule filler application. Resources not controlled by a schedule are not identified on a schedule request using this segment. Location resources are identified with this specific segment because of the specific encoding of locations used by the HL7 specification.
Scheduling segments carry the appointment story in pieces: request, service, resource group, location, personnel, preferences, and timing.
The v2.5.1 structures show AIL in SIU_S12 (Notification of new appointment booking), SQM_S25 (Schedule query message and response), SQR_S25 (Schedule query message and response), SRM_S01 (Request new appointment booking), and 1 other message structure. That tells you where it can appear, but the local implementation guide still decides which optional fields are meaningful.
Scheduling flows are easier to reason about when the request, resource, and appointment fields are visible together. HL7 Soup Web is helpful for inspection, and Integration Soup can keep resource mapping and routing rules explicit.
So this page stays intentionally practical: what each field is for, what shape the generated v2.5.1 data gives it, and where I would be careful before mapping it.
AIL-1 is the sequence number for this location resource line inside the appointment detail. It helps distinguish one AIL from another when a request has several rooms or locations attached. It is not the room code and it is not the appointment identifier.
AIL-2 is used when a location line is being added, changed, cancelled, deleted, or otherwise acted on in a scheduling update. Keep this aligned with the trigger event and the previous state of the appointment. A receiver that treats "change this room" and "remove this room" differently will not forgive a vague action code.
AIL-3 identifies the actual scheduled location, using the HL7 location shape rather than a loose text label. That might mean facility, point of care, room, bed, or another locally agreed location component. AIL is about the appointment's scheduled location resource, not necessarily the patient's current PV1 location.
AIL-4 is for the kind of location when the exact room is not known or not important yet. "Any exam room", "operating room", or "procedure room" is a different request from "Room 3, Level 2, City Clinic". If the filler later assigns the real location, it should return that in AIL-3.
AIL-5 can narrow the choice to a location pool: a campus, clinic area, theatre suite, modality area, or other local scheduling group. Use it to express a real scheduling constraint, not as a spare place for free-form site names.
The room or location may be needed at the appointment start, before it for setup, or after it for recovery or clean-up. AIL-6 sends an explicit time; AIL-7 and AIL-8 send an offset and unit from the appointment start.
Do not mix these casually. If the receiver expects offsets, agree whether negative values are allowed and what they mean. If the receiver expects absolute times, include the real precision and timezone behavior the scheduling system uses.
These fields describe how long the location is required when that differs from the overall appointment. A procedure room may be blocked longer than the patient-facing service, or a waiting area may be needed for only part of the workflow.
Use a positive duration and clear units. If the field is empty, many implementations will treat the location as required for the appointment duration from the stated start point, which is only safe when both sides calculate appointment duration the same way.
AIL-11 answers the practical question: may the filler substitute a comparable location if the requested one is not available? That can be harmless for "any standard exam room" and unacceptable for a named operating room or specialized suite.
AIL-12 is the filler-side status of this location booking. It is useful in confirmations and notifications, but a placer should not usually send it as if it already knows the filler application's booking state.
Related links
- SCH - Scheduling Activity Information
- ARQ - Appointment Request
- RGS - Resource Group
- AIS - Appointment Information
- AIG - Appointment Information - General Resource
- AIP - Appointment Information - Personnel Resource
- APR - Appointment Preferences
- TQ1 - Timing/Quantity
- SIU_S12 - Notification of new appointment booking
- SQM_S25 - Schedule query message and response
- SQR_S25 - Schedule query message and response