There’s always a lot of talk about HL7 in Healthcare IT, so I wanted to take the opportunity to compile a basic fact sheet about it for people like me who are just starting to get involved. Here’s the most useful info I’ve come across.
For starters, what is HL7? HL7 stands for Health Level Seven.
From their website:
Founded in 1987, Health Level Seven International (HL7) is a not-for-profit, ANSI-accredited standards developing organization dedicated to providing a comprehensive framework and related standards for the integration, sharing, and retrieval of electronic health information that supports clinical practice and the management, delivery and evaluation of health service HL7’s 2,300+ members include approximately 500 corporate members who represent more than 90% of the information systems vendors serving healthcare.
Okay, so it’s an organization, but it doesn’t really explain what HL7 means. I’ve been reading through Tim Benson’s “Principles of Health Interoperability: HL7 and SNOMED“, and it contains a lot of valuable information on HL7 and Health IT. In it, I found a concise explanation of the 7 layers:
“Layer 7 – Application : addresses definition of the data to be exchanged, the timing of the interchange, and the communication of certain errors to the application.
Layer 6 – Presentation: is concerned with the syntax of information transfer between between end systems.
Layer 5 – Session: provides mapping between physical and logical sessions, including checkpoint recovery and restart.
Layer 4 – Transport: provides end-to-end transmission of data to the required quality of service.
Layer 3 – Network: is concerned with routing with routing and relaying between multiple sub-networks.
Layer 2 – Data-link: transmit a stream of bits from one network node to another with indication of errors and limited error correction.
Layer 1 – Physical: provide the interface to the physical communications medium.”
I think one of the things that really draws me to the HL7 model is how international and cooperative it is. I’m a big fan of the Open Source Software movement, and have been ever since I booted up Ubuntu Linux on a machine I thought would be broken forever. HL7 works towards establishing standards that can apply anywhere in the world, so that health care can become a global collective effort. In order to facilitate this, they allow anyone to participate. It’s so amazing! I think I will continue posting regularly with HL7 basics, but if you want to get involved right now, please check out their membership page and sign up as a volunteer. It’s free, and allows you to participate in the ongoing HL7 discussions.