Defines the implementation of the HL7 Version 2.2 Standard within Australian public and private hospitals. Covers the functions of patient admission, discharge and transfer (ADT) as these functions form the basis for all HL7 messages. Provides interpretation and guidance on which HL7 trigger events, segments and data elements are mandatory (required), optional or conditional (required, based on a condition), and relevant usage notes for the Australian health environment. Provides consistent use of data definitions and references to the National Health Data Dictionary.