Health Level 7 or HL7
HL7 is a set of international standards for transfer of medical data(records) between software applications used by various healthcare providers.
It’s refer to the 7th layer(Application layer) of OSI(Open System Interconnection) model.
Hospitals and other health care provider organizations have many different computer systems. All of these systems should communicate with each other recive/retrive informations.
Versions of HL7
1. HL7 v2.x
2. HL7 3.
HL7v2x:
HL7v2 standard is also known as Pipehat and it’s support hospital workflow and its created in 1989. We have a no.of versions for this standards,giving us,
HL7 v2.1
HL7 v2.2
HL7 v2.3
HL7 v2.3.1
HL7 v2.4
HL7 v2.5
HL7 v2.5.1
HL7 v2.6
HL7 v2.7
HL7 v2.7.1
HL7 v2.8
HL7 v2.8.1
HL7 v2.8.2
Message Structure:
Segments:
Every boxes are also called Segments. Segments are groups of data that each contain related pieces of information. Each segment has a carriage return (\r) at the end of it to demarcate the end of a segment.
Within a segment, each field is separated with the pipe character ( | ) and it’s also called “bar” in HL7 terminology.
Message Header:
Each segment begins with a three letter string called a header. In this picture, everything in a green box is a header (MSH, PID, NK1, and IN1). Note that the MSH header is special. A segment with an MSH header will always begin an HL7 message, and that segment is thus called the message header.
HL7V3:
The HL7 version 3 standard has the aim to support all healthcare workflows.HL7 v3 was published in 2005.The HL7v3 standard is opposed to HL7v2 and it is based on formal methodology and object oriented principles.
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