By way of comparison the International HL7 2.4 standard has the following message structure which is varied by the Australian localisation (See section 1.7).

International ORU Message Structure
ORU^R01           Unsolicited Observation Message
MSH               Message Header
{
  [
    PID           Patient Identification
    [PD1]         Additional Demographics
    [{NK1}]       Next of Kin/Associated Parties
    [{NTE}]       Notes and Comments
  [
    PV1           Patient Visit
    [PV2]         Patient Visit - Additional Info
  ]
  ]
  {
    [ORC]         Order common
    OBR           Observations Report ID
    {[NTE]}       Notes and comments
    [CTD]         Contact Data
  {
    [OBX]         Observation/Result
    {[NTE]}       Notes and comments
  }
  [{FT1}]         Financial Transaction
  {[CTI]}         Clinical Trial Identification
  }
}
[DSC]             Continuation Pointer