Standardising clinical data elements

We report the development and implementation of a methodology for standardising clinical data elements. The methodology, piloted using Tuberculosis (TB) and Acute Coronary Syndromes (ACS) domains, relies on clinicians for natural language definitions and on informaticists for computable specifications. Data elements are represented using the ISO 11179 standard, UML class, and activity diagrams. Over 2000 candidate data elements were compiled for each domain. Initial sets of 21 data elements for ACS and 139 for TB, plus 300 valid values, were standardised and made publicly available. The methodology is now used in HL7 for data element definition in other clinical areas.