Abstract
A major use of medical ontologies is to support coding systems for use in electronic healthcare records and messages. A key task is to define which codes are to be used where – to bind the terminology to the model of the medical record or message. To achieve this formally, it is necessary to recognise that the model of codes and information models are at a meta-level with respect to the underlying ontology. A methodology for defining a Code Binding Interface in OWL is presented which illustrates this point. It generalises methodologies that have been used in a successful test of the binding of HL7 messages to SNOMED CT codes.