Message Structure
16 segments
R RequiredO Optional Choice
MSH
R1PATIENT
O1PID
R1PD1
O1NK1
O*NTE
O*VISIT
O1PV1
R1PV2
O1ORDER_OBSERVATION
R*ORC
O1OBR
R1NTE
O*CTD
O1OBSERVATION
R*OBX
O1NTE
O*FT1
O*CTI
O*DSC
O1Used by Events:R01ORU/ACK - Unsolicited transmission of an observation message