Message Types
16 message types in HL7 v2.1
§2.16.1 Message Type Table:Message types identify the purpose and content category of an HL7 message. Each type (e.g., ADT, ORM, ORU) represents a specific clinical or administrative domain and groups related trigger events that share common processing requirements.
ACK
General Acknowledgment CNT II
32 response•General
ADR
ANCILLARY RPT (DISPLAY)
1 response•ADT Response
ADT
ADT Message
23 trigger•Patient Admin
BAR
Add/Change Billing Account BLN VI
2 trigger•Billing
DFT
Detail Financial Transactions
DFT_P03•Financial
DSR
Display Response QRY V
12•Display Response
MCF
Delayed Acknowledgment CNT II
1 response•General
NUL
No Message Required (for Referential Integrity)
0 events•General
OCF
ORDER CONFIRMATION
0 events•Orders
ORF
Observ. Result/Record Resp. ANR VII
1 response•Observations
ORM
Order ORD IV
ORM_O01•Orders
ORR
Order Response Message ORD IV
ORR_O02•Order Response
ORU
Observ. Result/Unsolicited ANR VII
2 trigger•Observations
OSQ
Order Status Query ORD IV
0 events•Order Status
QRY
Query, Original Mode
5 trigger•Query
UDM
Unsolicited Display QRY V
UDM_Q05•Unsolicited