Introduction to HL7 Standard - Common HL7 Message Types

*HL7 content transport via MLLP (Minimal Lower Layer Protocol)

*HL7 is a connection oriented - ACK is a must

• ACK (General acknowledgement) - including original mode acknowledgements and enhanced mode acknowledgements

Original Mode Acknowledgement â€“ a “Receive” ACK, and 95% of the ACKs used in HL7 communications; indicates that a message has been received but not necessarily processed yet.

Enhanced Mode Acknowledgement â€“ an “Application” ACK that is a resultant status return rather than a communication response (i.e. query results, order response, etc.).

• ADT (Admit, Discharge, Transfer) - for Patient Administration.

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.).

• ORM  - Order (Pharmacy/treatment)

The HL7 ORM-O01 message functions as a general order message that is used to transmit information about an order. There is only one type of ORM message – the ORM-O01 message. Trigger events for the ORM-O01 message involve changes to an order such as new orders, cancellations, information updates, discontinuation, etc

• ORU - Observation result (unsolicited)

The HL7 ORU-R01 message transmits observations and results from the producing system/filler i.e. LIS, EKG system) to the ordering system/placer (i.e. HIS, physician office application).