Once you have acquired the data, you need to analyze it. You can analyze the data using the Message Browser. Other tools you can use are the command line tools called msgtransform and msgdiff. These tools can be used to process batches of HL7 messages.

Typically it is a good idea to start with an empty message definition file, then import just the segments you need to browse the message. Pick the segments defined in the highest version of HL7 you have available since these segments contain a superset of all known fields. For more information, see HL7 Version 2.X.

Before you import the segments they will appear highlighted in red. Recognized segments will appear in green.

The other tool that is very useful for data analysis is the command line msgtransform tool. The reason for this is that it makes it very easy to interactively test out your segment and table grammars. The procedure is very simple:

• Make a small change to the message definition file.
• Save it.
• Run the msgtransform tool.

This makes it very convenient to iteratively build up your message definition file. Typically you are probably going to be interested in running the tool in the 'table' mode, which tests out parsing each message into the defined table grammar. For example:

# adt.vmd is the message definition file used to parse the file
# the input messages are contained in 'input_messages.txt' 
# and the resulting output is put into the file 'output_report.txt'
> msgtransform --table adt.vmd input_messages.txt output_report.txt

The msgtransform utility is available for both Windows and Unix.

	Most versions of Windows and some Unix shells allow you to repeat previous commands by using the cursor up and down keys. Using this trick or making a little batch file or shell script is a nice convenient way to invoke the msgtransform utility.