Introduction of a hierarchy to LOINC to facilitate public health reporting.

Public health reporting of laboratory results requires unambiguous identification of the test performed and the result observed. Some laboratories are currently using Logical Observation Identifier Names and Codes (LOINC) for the electronic reporting of laboratory tests and their results to public health departments. Initial use revealed inconsistent identification and use of LOINC concepts by laboratories and public health agencies and an inability to systematically extend, for public health use, the tables when adding new concepts. We applied simple, logical rules to existing LOINC concepts to facilitate the creation of a hierarchy of concepts and to allow the identification and specification of appropriate terms for public health reporting and subsequent data aggregation. The hierarchy also allows the systematic addition of new concepts further supporting public health reporting. Application of the hierarchy is illustrated by using all laboratory LOINC concepts assigned to the subset of microbiology test types (CLASS MICRO).