Rally to your standards: HL7 and the NHS
Many of the technological developments taking place in the NHS are underpinned by standards that help systems to talk to each other and to understand what is being said when they do. One of these standards is HL7, a language developed to help healthcare systems exchange data with each other.
One of the biggest factors limiting the value of past investments in administrative and clinical IT systems has been the lack of common standards for exchanging data between them.
When combined with the sheer complexity of the different types of data used in healthcare, this has led to a situation in information is held in `silos'. Systems are unable to communicate easily with each other, or share data so better patient care can be delivered.
It was to overcome these types of problems that the National Programme for IT in the NHS was set to up in 2002. It was to work through "ruthless standardisation" of both computer systems and data standards. The strategy document that established the programme, said:
"To avoid duplication of effort and resources and to ensure that the benefits of ICT integration across health and social services are achieved. stringent standards [should be] set from the centre to ensure that systems across the UK are fully compatible with each other."
The key data standard chosen by the programme to enable electronic data exchange between systems was HL7, the main international standard for communication between various systems employed in the healthcare industry.
A common language for health IT
HL7 is a common language used by healthcare software systems to talk to one another. Within the national programme, HL7 provides the basis to help ensure that information is available when and where it is needed.
The HL7 standard is backed by the vast majority of IT suppliers working in the healthcare sector, including Microsoft. Its BizTalk Server includes an HL7 accelerator that simplifies the implementation of HL7 messages.
Why common standards matter
The value of common standards can be most easily illustrated by looking at other industries. For example, it is only because common data standards have been developed and adopted that someone using one email application can send an email to someone using a quite different email system.
Hospitals typically have many different computer systems that are used for everything from patient administration to electronic medical records and electronic prescribing. HL7 provides a language for these different systems to communicate - or interface - with each other.
For example, through the effective use of HL7, a patient's registration details can be electronically passed, when needed, from a hospital's patient administration system to a booking system and an order communications system - without the same data having to be re-captured and re-keyed each time.
A specialised, common healthcare language is also required to help computers cope with the complexity of everyday speech. Computers cannot, for instance, deal with synonyms (saying the same thing using different words) or homonyms (where the same term or phrase means different things in different contexts), both of which occur frequently when people talk about healthcare.
Speaking the same language
Unless a common language such as HL7 is used, a laborious and expensive translation service has to be put in place every time different clinical and administrative systems need to talk to one another.
But moving to standard messages will require a new degree of standardisation of clinical processes within the NHS. This is because many alternative, processes require a lot of different and optional data, whereas standard processes result in simpler, standard messages.
What are HL7 messages?
HL7 messages are XML (extensible mark-up language) documents, which look somewhat similar to HTML (which may be familiar from websites). Each message is a string of text with information enclosed by tags, wrapped in angle brackets. Start tags look like <tag> and end tags look like </tag>. Tags can be qualified by attributes such as <tag attribute="value">.
What is HL7 v3?
The intention is for HL7 v3 to become the new common language of the clinical computer systems being purchased under the NPfIT.
HL7 has been developed over the past 20 years and consists of standards for the exchange, integration, sharing, and retrieval of electronic health information to support clinical practice and the management, delivery and evaluation of health services. The latest version of HL7, and the one adopted by NPfIT, is HL7 v3.
Two versions of HL7 are in use within the NHS: version 2 and version 3. Version 3 is used for NPfIT national applications such as the NHS Spine (the `backbone' of the NHS Care Records Service) and the Choose and Book electronic booking system, while version 2 is mainly used within individual hospitals.
The cornerstone of HL7 v3 is the Reference Information Model (RIM). Crucially, the RIM expresses the data content needed in a specific clinical or administrative context and provides an explicit representation of the semantic and lexical connections that exist between the information carried in the fields of HL7 messages. The RIM is essential to increasing precision and reducing implementation costs.
Further Reading