Lp Outline 2
  • I. Description of hl7 and its purpose/Introduction
    • A. What it is
      • 1. HL7 stands for health level 7
        • a. Health level 7 international is one of many American National Standards Institute (ANSI) accredited Standards Developing organizations involved in health care today.
        • b. The name comes from the seven levels of the Open Systems Interconnection model. Level 7 is the application level.
        • c. It is an all-volunteer non-profit organization.
          • i. Health level 7 focuses on clinical and administrative data standards.
    • B. Where did it come from?
      • 1. It was founded in 1987.
      • 2. The American National Standards Institute (ANSI) recognized it in 1994.
    • C. Why it is used
      • 1. To create a standard in hospital information systems
        • a. The standards are designed to improve care delivery optimize workflow, reduce ambiguous data, and make the transfer of information a smooth process between hospitals, government agencies, and healthcare providers run smoothly.
      • 2. Saves time
        • a. Before hl7 every interface between systems was custom designed and required a lot more work.
    • D.Messages
      • 1. a hl7 message is a way to transmit data between disperate systems. Each message consists of a group of segments in a defined sequence
        • a. message types
          • i. identified by a 3 character code and are used in conjunction with a trigger event, which is a real world event that initiated communication and the sending of a message. Message type and trigger event make up the MSH-9 field of the message
            • a. MSH-9 field containing ADT-A01 means that ADT is the message type and A01 is the trigger event.
          • ii. popular message types
            • a. ACK – General Acknowledgement
            • b. ADT – Admit Discharge Transfer
            • c. BAR – Add/change billing account
            • d. DFT – Detailed financial transaction
            • e. MDM – medical document management
            • f. MFN – Master files notification
            • g. ORM – Order (pharmacy/treatment)
    • E. Who uses it?
      • 1. Users of hl7 are typically divided into 3 segments
        • a. Clinical interface specialists
          • i. these types of people deal with moving clinical data, create tools that make it possible to move the clinical data, or creating clinical applications that need to share or exchange data with other systems. They are responsible for moving clinical data between applications or healthcare providers.
        • b. Government or other politically homogeneous entities
          • i. these types of people look toward to future of sharing data across multiple entities or in future data movement. They would like to mandate a messaging standard.
        • c. Medical informatists
          • i. work within the field of health informatics (the study of logic of healthcare and how clinical knowledge is created). These types of users seek a form of hierarchical structure of healthcare knowledge, terminology and workflow.
  • II. Overview of hl7 version 2
    • A. How long it has been used
      • 1. Version 2 came out in 1989 and is still used today.
      • 2. Version 2.3 and 2.3.1 are most commonly used today approximately 75% of users use one of those 2 versions.
    • B. Where its used
      • 1.Going back to the users of hl7, version 2 was mostly created by the users of applications(the clinical interface specialists) It was very user led and real world focused
        • i. The initial goal of hl7 2 was avoiding large amounts of custom expensive coding and to create something that didn’t have 100% custom interfaces for everything.
        • ii. the group loosely defined an implied data model partially because they did not have a standards history to rely on.
        • iii. there was a big issue with a lack of interest from the major application vendors at the time
    • C. Common flaws/complaints about version 2
      • 1. It provides somewhat loose and optional standards and is too customizable.
        • a. can lead to discrepancies and miscommunication in hl7 interfaces
        • b. it may be preferred by a users standpoint but isn’t preferred by government officials and medical informaticsts
        • c. there are no precise standards
      • 2. It is not inclusive of international needs
        • a. need to support the need for local variants
      • 3. No compatibility with version 3
      • 4. Defining a detailed list of items to be discussed and negotiated before interfacing can occur is required.
  • III. Overview of hl7 version 3
    • A. When it came out
      • 1. Development started in 1995, came out in 2005
    • B. New things in version 3
      • 1. Its based on a formal methodology (the HDF) and object-oriented principles
      • 2. Top Down message development emphasizing reuse across multiple contexts and semantic interoperability
      • 3. Representation of complex relationships
      • 4. Formalisms for vocabulary support
      • 5. Support for large scale integration
      • 6.solving re-use interoperability across multiple domain contexts.
      • 7. A Uniform set of models
        • a. 90% or more of the interface is predefined.
        • b. the new standard is an explicit data model, clear definitions and less flexibility in individual message elements.
          • i. this was done to create a tighter standard and overall easier interface for users.
      • 8. Expanded scope to include community medicine, epidemiology, veterinary medicine, clinical genomics, security, etc.
      • 9. Version 3 is XML Based.
    • C. Who/Where and why it is used
      • 1. It is only used by a very small percentage of the people that use hl7.
      • 2. Government entities have begun to plan on using it to create interfaces between systems that have been separate in the past.
      • 3. Healthcare entities in Europe, Canada, and Germany have launched initiatives to implement Version 3.
  • IV. Differences and similarities between the two versions
    • A. Differences
      • 1. Beneficial differences of v2 over v3
        • a. reflects the complex “everyone is special” world of healthcare
        • b. its less expensive to build hl7 interfaces compared to custom interfaces
        • c. it provides 80% of the interface and a framework to negotiate the remaining 20% interface by interface basis
        • d. historically built in an ad hoc way, allowing most critical areas to be defined first
        • e. generally provides compatibility in any of the 2.X versions
      • 2. Beneficial differences of v3 over 2
        • a. More of a “true standard” and less of a “framework for negotiation”
        • b. Model-based standard provides more consistency
        • c. Application roles are well defined
        • d. less message options
        • e. Less expensive to build and maintain mid-to-long term interfaces
    • B. Similarities
      • 1. Both versions are growing. Some start with and/or switch two version 3 while version 2 is growing in usage
    • C. Compatibility
      • 1. Version 2 is not at all compatible with version 3
      • 2. All version 2.X (example 2.3 with 2.6) are compatible with one another.
  • V. Reasons why people dont switch to version 3/Conclusion
    • A. problems with upgrading
      • 1. Because they aren’t compatible with one another it would be an extremely difficult process to upgrade from v2 to v3.
        • a. the process of changing would involve maintaining version 2 while converting everything from version 2 to be compatible with version 3.
      • 2. People are less likely to start out with version 3 when it is only used by such a small percentage of the hl7 world.
        • a. the whole point oh hl7 is to have standardized data that makes it easy to communicate…it would be pretty difficult if you were using version 3 and everywhere else is using a 2.x version that isn’t compatible.
    • B. Way to get people to switch to version 3
      • 1. If the government enforced a rule to switch to version 3 and possibly provided assistance in the transition process.
        • a. it would be costly but in the end it would lead to easy communication and far less headaches down the road.