ICD, LOINC, and RxNORM Hierarchies

Standard medical code hierarchies are structured systems of codes that classify health-related information, such as diseases, procedures, laboratory tests, and medical products. They are created to standardize the categorization of clinical information across various healthcare settings. These hierarchies are adopted by researchers and health professionals as universal languages in healthcare, facilitating the accurate communication of medical data in clinical operations, billing processes, and healthcare research.

The medical hierarchies also present a tree-like structure that illustrates the relationships between complex medical terminologies, organizing information from the most specific (lower-level nodes) to the most general (higher-level nodes). This structure significantly aids the code roll-up process, which is essential for clinicians and medical researchers seeking to extract meaningful patterns and trends from detailed data sets. By aggregating individual codes into broader groups, researchers and clinicians can simplify detailed terminologies into more general phenotypes for higher-level analyses. Inspired by this prevalent need, we developed three applications designed to enhance the visualization of hierarchies in the domains of diagnosis, medication, and laboratory. These tools facilitate the querying of clinical terms and support advanced clinical research by providing a more accessible and comprehensive view of medical data.


ICD Hierarchy

The Phecode to ICD map showcases the knowledge graph mapping the relationship between International Classification of Diseases (ICD) coding system and Phecode system.

ICD Hierarchy
LOINC Hierarchy

LOINC (Logical Observation Identifiers Names and Codes) is a standardized coding system used globally to report laboratory and other clinical observations. The LOINC database contains over 71,000 terms, each described by a six-part structure that includes component, property, time aspect, system, scale, and method.

LOINC Hierarchy
RxNORM Hierarchy

This tool illustrates the hierarchical structure of medications and their variants in brand and dosage form denoted in RxNorm systems. It also showcases the knowledge graph mapping medicine in RxNorm code to other common medicine coding systems, such as ATC and VA.

RxNORM Hierarchy