Terminology use in electronic health records: basic principles.

Electronic health records (EHRs) are a cost-saving and environmentally friendly means for documenting patient care and improving patient safety, quality, and evidence-based practice. Standardized clinical classification systems and terminologies are essential ingredients of the EHR. Their selection must be driven by a clear understanding of requirements for their use and application. This article describes the principle uses of clinical information and motives for consistency in practice, and provides a distinction between classification systems and reference terminologies for clinical settings.