Compositional concept representation using SNOMED: towards further convergence of clinical terminologies.

This paper describes several approaches to the expression and coding of clinical concepts as composites of elementary entities, and describes an approach based on SNOMED RT that may permit further convergence of clinical terminology efforts. We explain the shortcomings of previous approaches to compositional concept representation, as well as the reasons for SNOMED's current approach, which adopts a foundation based in description logics (DLs). The DL model has many advantages: it establishes a formal semantics for SNOMED assertions and suggests a syntax; it provides a basis for understanding expressiveness and computational complexity, through correspondence with known results from DLs; and it helps to clarify the relationships among existing concept representation methods in SNOMED, NHS Clinical Terms (formerly the Read Codes), and GALEN, making a path to convergence more clear.