Tutorial: Transforming Messages – HL7 to HL7

This post was originally written for Iguana 5 so it contains version 5 screenshots, and may contain out of date references.

In this tutorial you will learn how to transform message data. We will copy an incoming HL7 message, correct a misspelled code, capitalize patient names, and forward the outgoing HL7 message.

These are the steps:

  1. Preparation: Parse the message into a source HL7 node tree structure
  2. Preparation: Create a target node tree with the same HL7 node tree structure
  3. Preparation: Copy the data from source to target using node:mapTree{}
  4. Transform the message to modify the data in some way, e.g., capitalize names etc.

This tutorial only addresses the last step, the preparatory steps have already been completed for you.

We recommend that you type in the code for each step, but we also include complete Sample Code if you prefer to paste it in and follow along.

Create the Channel [top]

  1. Create a Channel with the the following settings:
    • Source = LLP Listener
    • Destination = LLP Client
    • Channel name = Transformation HL7 to HL7
  2. Activate the Filter Component: Click the Filter tab and check Use Filter.
  3. Click the Add Channel button to create the channel.
    Ignore the red warning messages, see resolving the commit configuration error.
  4. Open the Translator by clicking the Edit Script link at the bottom of the Filter tab.
  5. Download and import the Transformation_HL7_to_HL7_Filter.zip project file.
    This file contains a skeleton project and six sample HL7 messages.
  6. Iguana will load the project and data into the Translator, your screen should look like this:

Tutorial Instructions [top]

  1. Pass the message data to the script.
    • Iguana automatically passes the message data to the main() function
    • The message can be accessed using the Data parameter
    • No action is needed
  2. Parse the message, create the outgoing message, and map the message.
    • The code for this is included from the imported project zip file
    • No action is needed
  3. An incorrect code of “Mix” is used for mixed race, we will use an “if” statement to change this to “Mixed” when it occurs.
    Replace line 10 with this if statement code, auto-completion will help you to find the fields and methods:
  4. Navigate through the sample messages to see the spelling correction in action.
    1. First add a trace() statement on the next line, and click on the Msg and Out (ADT) annotations to view them:
    2. Click through the sample messages, here the “MIX” race code is corrected:
  5. Capitalize the patient Given Name and Surname.
    1. First we need to use the stringutil module, so add this line of code at the top of your script:
    2. Then add these two lines of code:
      Screen Shot 2014-10-02 at 13.38.14
  6. Navigate through the sample messages to see how patient names are capitalized.
    1. First add a trace() statement on the next line, and click on the Msg and Out (ADT) annotations to view them:
    2. Then click through the sample data, here the patient surname has been corrected:

Complete Sample Code [top]

Here is the completed transformation code that you can cut and paste into your script.

require 'stringutil'

function main(Data)
   -- Parse the HL7 message
   local Msg, Name = hl7.parse{vmd = 'example/demo.vmd', data = Data}
   local Out       = hl7.message{vmd = 'example/demo.vmd', name = Name}
   
   -- Map the complete message
   Out:mapTree(Msg)
      
   -- (1) Transform the message data
   
   -- Correct misspelling of the Race Code
   if Out.PID[10][1][1]:nodeValue():lower() == "mix" then
      Out.PID[10][1][1] = "Mixed"
   end
   
   -- Capitalize patient Given Name and Surname
   Out.PID[5][1][2] = Out.PID[5][1][2]:nodeValue():capitalize()
   Out.PID[5][1][1][1] = Out.PID[5][1][1][1]:nodeValue():capitalize()
  
   -- Push the outgoing message into the Iguana queue
   queue.push(Out)
end

More Information [top]

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