HL7 - Glue for an Electronic Health Record (EHR)

HL7 or Health Level Seven is the glue that will hold together the pieces of the electronic health record (EHR) of tomorrow. The world has an aging population which demands ever higher standards of healthcare. One key enabler of delivering that healthcare is providing the right information, at the right time to clinicians so that they can make better decisions. HL7 is a communication and data protocol that allows information gathered by care providers and service providers in one application to be accessible to other care providers and service providers in other applications.

History of HL7

HL7 was developed by HL7 Inc a not for profit ANSI accredited development organisation.

HL7 Message Structure

HL7 messages have the following structure:

HL7 messages are composed of segments (separated by a carriage return character – hexadecimal 0A)
HL7 segments are composed of fields (separated by a field separator – typically the "|" character)
HL7 fields are composed of components (separated by a components separator – typically the "^" character)
HL7 components are composed of subcomponents (separated by a subcomponents separator – typically the "&" character)
HL7 fields may repeat (separated by a repetition separator – typically the "~" character)

Scope of HL7 Version 2

HL7 V2 covers events, segments and messages for a diverse range of health information domains. These include

patient administration
pathology/radiology order entry and results reporting
medication management (including prescribing, dispensing, and administration
document management
appointment scheduling
primary care referral
problem oriented record
laboratory automation
master files (code tables)

HL7 Version 3 – A new beginning

HL7 V3 represents a departure from the V2 approach. HL7 V3 uses a well defined methodology based on a reference information model (RIM). HL7 V3 has been under development for some time and represents the future focus of the HL7 standards process.