When you create or edit your HL7 Postmasters you are asked to select the HL7 Definition (see Creating Postmasters) which that Postmaster will use. It's very easy for customers to become confused as to exactly which HL7 Definition they should choose because they don't know which versions of HL7 they might be processing, or they are receiving different versions of HL7 from different sources, etc.
To help relieve some anxiety, it might help you to know that with very, very few exceptions it doesn't matter to the HL7 Postmaster which HL7 definition you choose. ANY Definition for HL7 Version 2.xx can be used to process ANY HL7 message which is version 2.xx. So if you're unsure, or don't have an opinion either way, then we recommend that you choose the HL7 Definition for HL7 Version 2.3. Why do we recommend this? No particular reason (remember ANY one of them will work), except that probably 70-80% of all HL7 interfaces in the world today still use HL7 Version 2.3 or 2.3.1 (click here to see) which are bundled in our Default Version 2.3 definition.
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Q: |
If it doesn't matter, why do I have to select one at all? |
A: |
While it has little effect on actually running the Postmaster, it might matter to YOU which HL7 Definition you choose, because your choice does have some small effects on how the program behaves when you are creating your Destinations and Data Sources. Read on below. |
The HL7 Definition contains exactly what you probably think it does. It's got a listing of the HL7 Message Segments, Fields and Data Types relating to a particular HL7 Version or Specific Vendor's implementation. It also contains many descriptions of fields and data types, HL7 internal tables, User Annotations, etc.
The HL7 Postmaster configuration program will USE the HL7 Definition selected for that Postmaster when you do things like creating destinations and entering Matching Instructions or Transformation Instructions to provide the list of HL7 segments you have to choose from in those windows. So if on your Postmaster you have selected the "Default" definition for HL7 version 2.2 then when adding or editing Matching Instructions you will only have the HL7 segments which were actually in HL7 version 2.2 to choose from in the list of segments.
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Q: |
That sounds really serious. What if the segment I want isn't in the list? |
A: |
You just type in the 3 character segment name you want if it's not in the list for you to choose. |
IMPORTANT NOTE: There is ONE feature of the Transformation Instructions which uses the HL7 Version Definition more extensively. It deals with using HL7 Internal Tables, see Using HL7 Tables In Macros for more information.
Other Uses for the HL7 Definitions:
Reports
A simple definition of HL7
HL7 Messages are made up of HL7 Segments. HL7 Segments are made up of HL7 Fields. HL7 Fields are each a specific HL7 Data Type and the Data Type is made up of Components. The actual DATA is contained in each Component.
So to reference a specific piece of data you need to know which Component of which Field of which Segment contains the data you want. You will usually see this in practice in different HL7 documentation or interface user's guides with varying types of notation. For instance if you want to reference the Patient's Last Name (Surname), that's in Field #5 of the PID segment. Field #5 of the PID segment is an HL7 Data Type XPN of which the first component is the Last Name (Surname). This is quite lengthy to write for every piece of data so in documents you might see the same piece of data referenced like this: PID 5.1 (short for PID segment, Field 5, Component 1).
HL7 Message Manifest Report
#1 MSH - Message header segment ======================================================= Raw Value: MSH|^~\&|Hospital 1|Lab 2|EMR|388146|20111030233915^S|NO SECURITY|ADT^A08|2011103023391500011|T|2.3|000000000611811||AL| ======================================================= #2 EVN - Event type segment ======================================================= Raw Value: EVN|A08|20111030233915^S||00102|00002| ======================================================= #3 PID - Patient identification segment ======================================================= Raw Value: PID||38814627|2227524181|234166342|Hansen^Hazel^M||19800316|M|Hansen^Imogen|Asian|3881 Goldsbrough Lane^APT215^Placentia^PA^746943221||(746) 943-2217|(214)555-1212X00019||||746943221710|746-94-3221| ======================================================= #4 PV1 - Patient visit segment ======================================================= Raw Value: PV1||P|^^^00002|R||00019|06543^HOOPER^DENNIS^L|||||||||||||00111| ======================================================= #5 DG1 - Diagnosis segment ======================================================= Raw Value: DG1|0001|I9||NODX||W|||||||||01|06543^HOOPER^DENNIS^L| ======================================================= #6 GT1 - Guarantor segment ======================================================= Raw Value: GT1|0001|1565221281|Powell^Peter^S||5008 SOMEPLACE RD^APT215^FT WORTH^TX^76132-0000|(817)555-1212|(214)555-1212X00019| ======================================================= #7 IN1 - Insurance segment ======================================================= Raw Value: IN1|0001|0000008|0000114|UNITED HEALTH 87726|P O BOX 740800^^ATLANTA^GA^30374-0800||(800)842-5724|||||20000401|||P|OYLE^OLIVE^M|00002|19760824|5008 SOMEPLACE RD^APT215^FT WORTH^TX^76132-0000|Y|Y||||||A|||||||||234166342|||||||F| ======================================================= #8 IN2 - Insurance additional information segment ======================================================= Raw Value: IN2||234166342|0009999^UNKNOWN||I| ======================================================= MSH - Message header segment (20 defined fields. 15 fields in the segment. 12 fields contain data) ============================================================ Raw Value: MSH|^~\&|SOMEAPP|SOMEAPP|YOURAPP|YOURAPP|20031111163831+0000^S|NO SECURITY|ADT^A08|153681279959711|T|2.3|00051||AL| ============================================================ MSH-1: RESERVED (Field Delimiter) MSH-2: RESERVED (Encoding Characters) MSH-3: Sending Application [HD] [3 components] #1 [IS] namespace id: SOMEAPP #2 [ST] universal ID: #3 [ID] universal ID type: MSH-4: Sending Facility [HD] [3 components] #1 [IS] namespace id: SOMEAPP #2 [ST] universal ID: #3 [ID] universal ID type: MSH-5: Receiving Application [HD] [3 components] #1 [IS] namespace id: YOURAPP #2 [ST] universal ID: #3 [ID] universal ID type: MSH-6: Receiving Facility [HD] [3 components] #1 [IS] namespace id: YOURAPP #2 [ST] universal ID: #3 [ID] universal ID type: MSH-7: Date/Time Of Message [TS] [2 components] Raw Value: 20031111163831+0000^S #1 [ST] Time stamp data: 20031111163831+0000 #2 [ST] degree of precision (optional): S MSH-8: Security [ST] [1 components] #1 [ST] string data: NO SECURITY MSH-9: Message Type [CM] [4 components] Raw Value: ADT^A08 #1 [ST] Component 1: ADT #2 [ST] Component 2: A08 #3 [ST] Component 3: #4 [ST] Component 4: MSH-10: Message Control ID [ST] [1 components] #1 [ST] string data: 153681279959711 MSH-11: Processing ID [PT] [2 components] #1 [ID] processing ID: T #2 [ID] processing mode: MSH-12: Version ID [VID] [3 components] #1 [ID] version id: 2.3 #2 [CE] internationalization code: #3 [CE] international version ID: MSH-13: Sequence Number [NM] [1 components] #1 [ST] Numeric data: 00051 MSH-14: Continuation Pointer [ST] [1 components] #1 [ST] string data: MSH-15: Accept Acknowledgment Type [ID] [1 components] #1 [ST] Coded value for HL7 Tables: AL MSH-16: Application Acknowledgment Type [ID] [1 components] #1 [ST] Coded value for HL7 Tables: MSH-17: Country Code [ID] [1 components] #1 [ST] Coded value for HL7 Tables: MSH-18: Character Set [ID] [1 components] #1 [ST] Coded value for HL7 Tables: MSH-19: Principal Language Of Message [CE] [6 components] #1 [ST] identifier: #2 [ST] text: #3 [ST] name of coding system: #4 [ST] alternate identifier: #5 [ST] alternate text: #6 [ST] name of alternate coding system: MSH-20: Alternate Character Set Handling Scheme [ID] [1 components] #1 [ST] Coded value for HL7 Tables:
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