Comments on: HL7 Escape Sequences

By: Tweets that mention HL7 Escape Sequences | HL7 Standards -- Topsy.com

Tweets that mention HL7 Escape Sequences | HL7 Standards -- Topsy.com — Fri, 11 Feb 2011 16:03:22 +0000

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By: marchewek

marchewek — Fri, 11 Feb 2011 12:02:00 +0000

It’s because unescaping escaped characters should occur only once – Cade2 won’t get interpreted. If there was a character you wanted to escape, e.g. ą – “ącade” it should be escaped (the number I’m about type now is random) E\C1234cadeE – notice double backslash. Then unescaping would produce: E – , C1234 – ą, cade – cade, E -

By: Mike Stockemer

Mike Stockemer — Thu, 10 Feb 2011 17:39:00 +0000

You are correct. The escape character is set in MSH-2, and if you set it to * then the escape sequences would use that character. Most applications use the suggested encoding characters. McKesson Star is one application that you typically run into that modifies MSH-1 and MSH-2. You know you are interfacing with Star when you see lots of : and ; characters in the HL7 messages.

By: Anonymous

Anonymous — Thu, 10 Feb 2011 17:22:00 +0000

David, the parser should not get confused. when it parses and finds the ” character it knows that is a special character and what follows is some sort of escape sequence. It’s really no different than escape sequences in other languages such as XML. If you want to send an ampersand ‘&’ in an XML document you must escape it as ‘&’

You should not attempt to send binary data in an HL7 message, it should be encoded prior to sending. Typically interfaces will Base64 encode binary data prior to sending it across an interface. Just like e-mail typically uses Mime encoding to deliver binary data.

By: marchewek

marchewek — Thu, 10 Feb 2011 16:35:00 +0000

I undestand that all sequences (eg. H) look like this because is the escape character, don’t they?
If the escape character was *, then these sequences’d look like *H* – am I right?

By: David Wong

David Wong — Wed, 13 May 2009 23:17:30 +0000

Suppose I have some unfortunate filename text that should be properly escaped such as “C:\Cade2\file.txt”, how should the string be escaped?
If I insert, “C:\E\Cade2\E\file.txt” won’t the HL7 encoder get confused by the \Cxxyy\ substring?

Another way this could much more easily happen is in inserting the data from a binary file into an ED field.

By: cynthia peters

cynthia peters — Fri, 01 Aug 2008 16:52:49 +0000

This is great information…and you guys are in out backyard.
Do you have any one day training seminars on Sat.
For basic HL7. I need a refresher.

By: Variations of the HL7 ORU^R01 Message Format

Variations of the HL7 ORU^R01 Message Format — Mon, 10 Sep 2007 15:51:50 +0000

[...] Notice also that the backslash characters () in the path need to be properly escaped using the HL7 escape sequence E. MSH|^~&|System1||||200707090801||MDM^T01|3542196|P|2.3 EVN|T01|200707090801|200707090801 [...]

By: HL7 Engine Mapping

HL7 Engine Mapping — Wed, 05 Sep 2007 14:04:51 +0000

[...] that inherits all the characteristics of the standard format – supports Z segments, non-standard separator characters, [...]