MSH
HL7 v2.x message header segment, always first.
Definition
MSH-1 is the field separator (|) and MSH-2 the encoding characters (^~\&). MSH-9 carries the message type (e.g. ADT^A01), MSH-10 the unique Message Control ID echoed by the MSA-2 acknowledgement, and MSH-12 the HL7 version. It opens every v2 message.
Origin
Defined in Chapter 2 (Control) of the HL7 Version 2.x Standard, published by Health Level Seven International.
Example in context
MSH|^~\&|SENDAPP|SENDFAC|RCVAPP|RCVFAC|20240620120000||ADT^A01|MSG00001|P|2.5.1