This Standard defines a uniform implementation of Chapter 3 of the Health Level Seven (HL7) Version 2.4 protocol. It is primarily designed for use within and between Australian and New Zealand health care settings. It covers patient administration functions, as these form the basis for most clinical health care messages. It also provides interpretation and guidance on which HL7 trigger events, segments and data elements are mandatory (required), or optional or conditional (required, based on a condition), and gives relevant usage notes for the Australian and New Zealand health environment. The Standard provides for consistent use of data definitions as well as commentary and references to the National Health Data Dictionary and the International Organization for Standardization (ISO). This Standard is referenced by other Australian Standards on how to implement HL7 and is required by implementers of those Standards.