ADT (Admission, Discharge, Transfer)
ADT messages are the foundation of patient administration systems. They track a patient’s lifecycle within a healthcare facility, from initial registration through discharge and any movements in between. These messages trigger updates across clinical, billing, dietary, and bed management systems, ensuring all departments have current patient location and status information. Most healthcare integrations begin with ADT because accurate patient demographics are prerequisites for all other clinical workflows.
ADT^A01 - Admit/Visit Notification
The ADT^A01 message is triggered when a patient is admitted to a healthcare facility. This message notifies receiving systems about the new admission and includes comprehensive patient demographics, insurance information, and visit details. Use this message type when registering inpatient admissions, emergency visits, or observation stays that require bed assignment and clinical tracking.
MSH|^~\&|ADT|HOSPITAL|RECEIVER|RECEIVING_FACILITY|20231117120000||ADT^A01|MSG00001|P|2.5
EVN|A01|20231117120000|||001^CLERK^ADMISSION
PID|1||123456^^^HOSPITAL^MR||DOE^JOHN^A||19800115|M|||123 MAIN ST^^CITY^ST^12345^USA||(555)555-5555|||S||987654321
NK1|1|DOE^JANE^|SPO|123 MAIN ST^^CITY^ST^12345|(555)555-5556
PV1|1|I|2000^2012^01^01^^^BED 01^BED||||004777^SMITH^JOHN^^^DR|||SUR||||ADM|A0|
IN1|1|PLAN001|INSURANCE_CO|INSURANCE COMPANY||||GRP123456|GROUP NAMEADT^A02 - Transfer Patient
The ADT^A02 message communicates that a patient has been transferred from one location to another within a healthcare facility. This message is essential for tracking patient movement between units, floors, or beds. When sending this message, the PV1 segment should reflect the new location, and systems use this information to update bed management, nursing assignments, and dietary services.
MSH|^~\&|ADT|HOSPITAL|RECEIVER|RECEIVING_FACILITY|20231117130000||ADT^A02|MSG00002|P|2.5
EVN|A02|20231117130000
PID|1||123456^^^HOSPITAL^MR||DOE^JOHN^A||19800115|M
PV1|1|I|3000^3045^02||||005888^JONES^MARY^^^DR|||MEDADT^A03 - Discharge Patient
The ADT^A03 message indicates that a patient has been discharged from the facility. This message triggers downstream systems to close the encounter, finalize billing, update census records, and potentially schedule follow-up appointments. The discharge disposition in PV1 provides important information about where the patient went (home, another facility, expired, etc.), which affects clinical reporting and reimbursement.
MSH|^~\&|ADT|HOSPITAL|RECEIVER|RECEIVING_FACILITY|20231117180000||ADT^A03|MSG00003|P|2.5
EVN|A03|20231117180000
PID|1||123456^^^HOSPITAL^MR||DOE^JOHN^A||19800115|M
PV1|1|I|2000^2012^01||||004777^SMITH^JOHN^^^DR|||SUR||||DIS|A0|ORM (Order Message)
ORM messages drive the clinical ordering workflow, connecting physicians with ancillary departments like laboratory, radiology, and pharmacy. When a clinician places an order in the EHR, the system generates an ORM message that routes to the appropriate fulfilling system. These messages support the full order lifecycle including new orders, modifications, cancellations, and discontinuations through different order control codes.
ORM^O01 - General Order Message
The ORM^O01 message is the workhorse of clinical ordering systems. It communicates new orders, modifications, and cancellations for laboratory tests, radiology studies, pharmacy prescriptions, and other clinical services. The ORC (Common Order) segment contains order control information such as whether this is a new order (NW), cancel (CA), or discontinue (DC), while the OBR segment specifies the test or procedure being ordered.
MSH|^~\&|CPOE|HOSPITAL|LAB|HOSPITAL|20231117120000||ORM^O01|MSG00004|P|2.5
PID|1||123456^^^HOSPITAL^MR||DOE^JOHN^A||19800115|M
ORC|NW|ORD123456|||||^^^20231117120000
OBR|1|ORD123456||CBC^COMPLETE BLOOD COUNT^LOCAL|||20231117120000ORU (Observation Result)
ORU messages deliver clinical results from diagnostic departments back to the ordering clinician and patient record. These are “unsolicited” messages sent automatically when results are finalized, rather than requiring a query. Laboratory systems, radiology departments, and other diagnostic services use ORU^R01 to communicate findings including numeric values, coded results, and narrative reports.
ORU^R01 - Unsolicited Observation Message
The ORU^R01 message delivers laboratory results, radiology reports, and other diagnostic findings from performing systems to clinical applications. This “unsolicited” message is sent automatically when results become available, without requiring a query from the receiving system. Each OBX segment contains a single observation value with its units, reference range, and abnormal flags. Results can have multiple status values: preliminary (P), final (F), or corrected (C).
MSH|^~\&|LAB|HOSPITAL|RECEIVER|HOSPITAL|20231117140000||ORU^R01|MSG00005|P|2.5
PID|1||123456^^^HOSPITAL^MR||DOE^JOHN^A||19800115|M
OBR|1|ORD123456||CBC^COMPLETE BLOOD COUNT^LOCAL|||20231117120000|||||||20231117140000|||004777^SMITH^JOHN^^^DR
OBX|1|NM|WBC^White Blood Count^LOCAL||7.5|10*3/uL|4.5-11.0|N|||F
OBX|2|NM|RBC^Red Blood Count^LOCAL||4.8|10*6/uL|4.5-5.5|N|||F
OBX|3|NM|HGB^Hemoglobin^LOCAL||14.5|g/dL|13.5-17.5|N|||F
OBX|4|NM|HCT^Hematocrit^LOCAL||43.2|%|41-53|N|||FSIU (Scheduling)
SIU messages coordinate appointment scheduling across healthcare systems. When appointments are booked, modified, or cancelled in a scheduling application, SIU messages notify other systems that need to prepare resources, update patient records, or display appointment information. Different trigger events indicate whether an appointment is new (S12), rescheduled (S13), modified (S14), or cancelled (S15).
SIU^S12 - Notification of New Appointment
The SIU^S12 message announces that a new appointment has been scheduled. This message type is used by scheduling systems to notify other applications about patient appointments, enabling downstream systems to prepare resources, update waiting lists, and coordinate care. The SCH segment contains appointment timing and duration, while AIG (Appointment Information - General Resource) and AIL (Appointment Information - Location Resource) segments specify the provider and location details.
MSH|^~\&|SCHEDULING|HOSPITAL|RECEIVER|HOSPITAL|20231117120000||SIU^S12|MSG00006|P|2.5
SCH|ORD789456||ORD789456||||CHECKUP^ROUTINE CHECKUP|||||60|MIN||||||20231120140000|20231120150000
PID|1||123456^^^HOSPITAL^MR||DOE^JOHN^A||19800115|M
RGS|1
AIG|1||004777^SMITH^JOHN^^^DR|||20231120140000|60|MIN
AIL|1||EXAM_ROOM_1^EXAMINATION ROOM 1|||20231120140000|60|MIN