HL7 ADT messages carry patient demographic information for HL7 communications but also provide important information about trigger events (such as patient admit, discharge, transfer, registration, etc.). Some of the most important segments in the ADT message are the PID (Patient Identification) segment, the PV1 (Patient Visit) segment, and occasionally the IN1 (Insurance) segment. ADT messages are extremely common in HL7 processing and are among the most widely used of all message types.
There are 51 different types of ADT messages that are used for various trigger events. Some of the most commonly used ADT messages include:
- ADT-A01 – patient admit
- ADT-A02 – patient transfer
- ADT-A03 – patient discharge
- ADT-A04 – patient registration
- ADT-A05 – patient pre-admission
- ADT-A08 – patient information update
- ADT-A11 – cancel patient admit
- ADT-A12 – cancel patient transfer
- ADT-A13 – cancel patient discharge
ADT messages are important in HL7 communications because they provide vital data about the patient and why the message is being sent. Trigger events are instrumental in driving message flow, because they determine when and where messages go based on the type of event that has occurred.
For instance, an ADT-A01 (patient admit) message might be sent to an Emergency Department system while an ADT-A04 (patient registration) message might be sent to an HIS system. The level of urgency and pace at which the message is transmitted might also be different depending on the trigger event.