MSH Segment Structure
| Sno | Element Name | Len | Data type | Usage | Table |
| 1 | Field Separator | 1 | ST | R | |
| 2 | Encoding Characters | 4 | ST | R | |
| 3 | Sending Application | 180 | HD | X | |
| 4 | Sending Facility | 180 | HD | R | |
| 5 | Receiving Application | 180 | HD | X | |
| 6 | Receiving Facility | 180 | HD | X | |
| 7 | Date/Time of Message | 26 | TS | R | |
| 8 | Security | 40 | ST | X | |
| 9 | Message Type | 13 | CM | R | |
| 10 | Message Control ID | 20 | ST | R | |
| 11 | Processing ID | 3 | PT | R | |
| 12 | Version ID | 60 | VID | R | 0104 |
| 13 | Sequence Number | 60 | NM | X | |
| 14 | Continuation Pointer | 180 | ST | X | |
| 15 | Accept Acknowledgement Type | 2 | ID | R | 0155 |
| 16 | Application Acknowledgement Type | 2 | ID | O | 0155 |
| 17 | Country Code | 3 | ID | X | |
| 18 | Character Set | 16 | ID | X | |
| 19 | Principal Language of Message | 250 | CE | X | |
| 20 | Alternate Character Set Handling Scheme | 20 | ID | X | 0211 |
| 21 | Conformance Statement ID | 30 | ID | R |
Usage Description:
| R | Required |
| RE | Required but may be Empty |
| O | Optional |
| C | Conditional |
| CE | Conditional but it may be empty |
| x | Not Supported |
MSH.1 – Field Separator
This field contains the separator between the segment. The recommended character is |, (ASCII 124).
Data type is ST – String
Examples:
MSH|^~\&|LAB|QTE||30218|20090714023209||ORU^R01|20090714235298399160|P|2.3|||||||
MSH.2 – Encoding Characters
This field contains the four characters in the following order: the component separator, repetition separator, escape character, and subcomponent separator. Recommended values are ^~\& (ASCII 94, 126, 92, and 38, respectively).
| Segment Terminator | <cr> | Terminates a segment record. This value cannot be changed by implementers. |
| Field Separator | | | Separates two adjacent data fields within a segment. It also separates the segment ID from the first data field in each segment. |
| Component Separator | ^ | Separates adjacent components of data fields where allowed. |
| Subcomponent Separator | & | Separates adjacent subcomponents of data fields where allowed. If there are no subcomponents, this character may be omitted. |
| Repetition Separator | ~ | Separates multiple occurrences of a field where allowed. |
| Escape Character | \ | Escape character for use with any field represented by an ST, TX or FT data type, or for use with the data (fourth) component of the ED data type If no escape characters are used in a message, this character may be omitted. However, it must be present if subcomponents are used in the message. |
MSH.3 – Sending Application
This field uniquely identifies the sending application among all other applications within the network enterprise. The network enterprise consists of all those applications that participate in the exchange of HL7 messages within the enterprise. Entirely site-defined.
Data type is HD
Components: <namespace ID (IS)> ^ <universal ID (ST)> ^ <universal ID type (ID)>
CL^57768-2
CP^387564
The value of <namespace ID> represents the high-level naming authority that controls the assignment of laboratory identifiers that appear in the <universal ID> component. The preferred naming authority is CLIA, and laboratories with a CLIA identifier must send that identifier in the <universal ID> component, along with the value “CL” in the <namespace ID> component
Examples:
MSH|^~\&|EPIC|EPICADT|SMS|SMSADT|199912271408|CHARRIS|ADT^A04|1817457|D|2.5|
MSH|^~\&|SHIEL|SHIEL|H_Dx|999994|200904100656||ORU^R01|SH13857997|D|2.3|
MSH|^~\&|ELYSIUMCONNECT|THA-I||TUH|20080722001201||ORU^R01|22001202527|P|2.2
MSH.4 – Sending Facility
This field uniquely identifies the receiving application among all other applications within the network enterprise. The network enterprise consists of all those applications that participate in the exchange of HL7 messages within the enterprise. Entirely site-defined.
Data type is HD.
Components: <namespace ID (IS)> ^ <universal ID (ST)> ^ <universal ID type (ID)>
MSH.5 – Receiving Application
This field identifies the receiving application among multiple identical instances of the application running on behalf of different organizations.
Entirely site-defined.Data type is HD.
MSH Segment Examples:
MSH|^~\&|Test|My CLINICAL LAB|Test|100|201309050000||ORU^R01||P|2.3|
