hl7 0.1.1

Simple library for parsing messages of Health Level 7 (HL7) version 2.x.

HL7 is a communication protocol and message format for health care data. It is the de facto standard for transmitting data between clinical information systems and between clinical devices. The version 2.x series, which is often is a pipe delimited format is currently the most widely accepted version of HL7 (version 3.0 is an XML-based format).

python-hl7 currently only parses HL7 version 2.x messages into an easy to access data structure. The current implementation does not completely follow the HL7 specification, but is good enough to parse the most commonly seen HL7 messages. The library could potentially evolve into being fully complainant with the spec. The library could eventually also contain the ability to create HL7 v2.x messages.

python-hl7 parses HL7 into a series of wrapped hl7.Container objects. The there are specific subclasses of hl7.Container depending on the part of the HL7 message. The hl7.Container message itself is a subclass of a Python list, thus we can easily access the HL7 message as an n-dimensional list. Specically, the subclasses of hl7.Container, in order, are hl7.Message, hl7.Segment, and hl7.Field. Eventually additional containers will be added to fully support the HL7 specification.

As an example, let’s create a HL7 message:

>>> message = 'MSH|^~\&|GHH LAB|ELAB-3|GHH OE|BLDG4|200202150930||ORU^R01|CNTRL-3456|P|2.4
'
>>> message += 'PID|||555-44-4444||EVERYWOMAN^EVE^E^^^^L|JONES|196203520|F|||153 FERNWOOD DR.^^STATESVILLE^OH^35292||(206)3345232|(206)752-121||||AC555444444||67-A4335^OH^20030520
'
>>> message += 'OBR|1|845439^GHH OE|1045813^GHH LAB|1554-5^GLUCOSE|||200202150730||||||||555-55-5555^PRIMARY^PATRICIA P^^^^MD^^LEVEL SEVEN HEALTHCARE, INC.|||||||||F||||||444-44-4444^HIPPOCRATES^HOWARD H^^^^MD
'
>>> message += 'OBX|1|SN|1554-5^GLUCOSE^POST 12H CFST:MCNC:PT:SER/PLAS:QN||^182|mg/dl|70_105|H|||F
'

We call the hl7.parse() command with string message:

>>> h = parse(message)

We get a hl7.Message object, wrapping a series of hl7.Segment objects.

>>> type(h)
<class 'hl7.Message'>

We can always get the HL7 message back.

>>> str(h) == message.strip()
True

Interestingly, this hl7.Message can be accessed as a list.

>>> isinstance(h, list)
True

There were 4 segments (MSH, PID, OBR, OBX):

>>> len(h)
4

We can extract the hl7.Segment from the hl7.Message instance.

>>> h[3]
[['OBX'], ['1'], ['SN'], ['1554-5', 'GLUCOSE', 'POST 12H CFST:MCNC:PT:SER/PLAS:QN'], [''], ['', '182'], ['mg/dl'], ['70_105'], ['H'], [''], [''], ['F']]

We can easily reconstitute this segment as HL7, using the appopriate separators.

>>> str(h[3])
'OBX|1|SN|1554-5^GLUCOSE^POST 12H CFST:MCNC:PT:SER/PLAS:QN||^182|mg/dl|70_105|H|||F'

We can extract individual elements of the message:

>>> h[3][3][1]
'GLUCOSE'
>>> h[3][5][1]
'182'

We can look up segments by the segment identifer:

>>> pid = segment('PID', h)
>>> pid[3][0]
'555-44-4444'

Project site: http://www.bitbucket.org/johnpaulett/python-hl7/wiki/Home

HL7 References:

• http://en.wikipedia.org/wiki/HL7

• http://nule.org/wp/?page_id=99

• http://www.hl7.org/

• http://openmrs.org/wiki/HL7

• http://comstock-software.com/blogs/ifaces/2007/01/hl7-message-wrappers.html