Using Segment Identities To Handle Multiple Message Versions |
In some circumstances, an application may be sending messages in two different formats. For example, suppose that the sending application is sending messages similar to the following:
MSH|^~\&|APP1|FAC1|APP1|FACILITY1|20070111102716||ORU^R01|070111110412558|P|2.5||||||||| PID|1||1111||BABYLASTNAME^BABE|||||||||||||||||||||||||| NK1|1|NEOMOTHER||||||||||||||4/4/1975 12:00:00 AM|||||||||||||||||||||| ORC|RE|||||||||||||||||||||||| OBR|1|1111|1111||||||||||||||||||||||||^^^||||||||||||||||||| OBX|1|ST|PKU^Phenylalanine||normal||||||||||||| OBX|2|ST|TSH-I-E^TSH Initial Elevated||high||||||||||||| |
MSH|^~\&|APP2|FAC2|APP2|FACILITY2|20060208122213||ORU^R01|060208122212558|P|2.6||||||||| PID|1||1111||BABYLASTNAME^BABE|||||||||||||||||||||||||| NK1|1|NEOMOTHER||||||||||||||4/4/1975 12:00:00 AM|||||||||||||||||||||| ORC|RE|||||||||||||||||||||||| OBR|1|1111|1111||||||||||||||||||||||||^^^||||||||||||||||||| OBX|1|NM|GALT^Galactose-1-phosphate uridyl transferase||22||||||||||||| OBX|2|NM|NTSH^Thyrotropin (thyroid stimulating hormone)||5||||||||||||| |
If you examine these messages, you will see that they are both ORU^R01 (Unsolicited Observation Message) messages. However, the first message uses version 2.5 of the HL7 standard and the second message uses version 2.6 of the HL7 standard. In the first message, the fifth field of each OBX segment (OBX.5) is a numeric value. In the second message, the fifth field of each OBX segment is text.
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In version 2.6 of HL7, the OBX.5 field is of variable type. The value of OBX.2 determines the type of the OBX.5 field. | ||
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Also notice the third field of the MSH segment in each message (MSH.3, or Sending Application). In the first message, this field is set to APP1. In the second message, this field is APP2. If you know that all messages of the first type have APP1 as their sending application, and all messages of the second type have APP2 as their sending application, you can use this information to distinguish one type of message from another.
In this tutorial, you will learn how to use Chameleon's segment identity capability to create a VMD file that contains separate message definitions for each of these message types. You will then create an Iguana channel that routes these messages to a database.