Terminology & standards

HDB-0072

SNOMED CT

SNOMED International SNOMED CT is a systematized nomenclature of medicine clinical terminology system maintained by SNOMED International, a non-profit organization. It provides standardized international multilingual clinical terminology used globally to code clinical findings, procedures, diagnoses, and medical concepts in healthcare systems. Terminology Credentialed HDB-0073

LOINC

Regenstrief Institute LOINC is an international standard for identifying health observations, measurements, and laboratory tests maintained by the Regenstrief Institute at Indiana University. It enables healthcare systems to identify, exchange, and aggregate clinical data using unique standardized codes for laboratory and clinical observations. Terminology Open access HDB-0074

RxNorm

National Library of Medicine RxNorm is a normalized naming system for generic and branded clinical drugs maintained by the National Library of Medicine, part of the NIH. It provides normalized drug names and links to drug vocabularies commonly used in pharmacy management and drug interaction systems for semantic interoperation. Terminology Open access HDB-0075

WHO ICD-11

World Health Organization The International Classification of Diseases 11th Revision (ICD-11) is the global standard for diagnostic health information maintained by the World Health Organization. It provides a standardized system for classifying diseases, disorders, injuries, and health conditions used worldwide for healthcare management and clinical documentation. Terminology Open access HDB-0076

UMLS

National Library of Medicine The Unified Medical Language System (UMLS) is a comprehensive repository of biomedical and health terminologies maintained by the National Library of Medicine, part of the NIH. It integrates over 100 medical vocabularies including SNOMED CT, LOINC, and RxNorm to enable interoperability and cross-referencing between different healthcare coding systems. Terminology Credentialed HDB-0077

DrugBank

University of Alberta DrugBank is a comprehensive online database containing detailed information on drugs, drug targets, and drug interactions created and maintained by the University of Alberta and The Metabolomics Innovation Centre in Canada. It provides structured biomedical knowledge on approved and experimental drugs used by researchers for drug discovery and pharmacology research. Terminology Free registration HDB-0078

WHO ATC/DDD Index

WHO Collaborating Centre for Drug Statistics Methodology The Anatomical Therapeutic Chemical (ATC) Classification System and Defined Daily Dose (DDD) system is maintained by the WHO Collaborating Centre for Drug Statistics Methodology hosted by the Norwegian Institute of Public Health. It provides an international standard system for classifying drugs and measuring medication usage in drug utilization research and monitoring. Terminology Free registration HDB-0079

OHDSI Athena

Observational Health Data Sciences and Informatics Athena is a web application for distributing and browsing standardized vocabularies for the Observational Medical Outcomes Partnership (OMOP) Common Data Model maintained by OHDSI. It integrates over 136 vocabularies including SNOMED CT, LOINC, and RxNorm to facilitate data harmonization across observational health research networks. Terminology Open access HDB-0480

MeSH (Medical Subject Headings)

National Library of Medicine (NLM/NIH) MeSH is the NLM's controlled vocabulary thesaurus organized in a hierarchical structure and used for indexing articles in PubMed and the NLM catalog. It contains thousands of descriptors (main headings) and qualifiers (subheadings) for systematically indexing biomedical literature, and is maintained through continuous updates to incorporate new terms from the scientific literature. Terminology Open access HDB-0481

HL7 FHIR Terminologies

Health Level Seven (HL7) International HL7 FHIR (Fast Healthcare Interoperability Resources) Terminologies define the standard codes, value sets, and code systems for healthcare data exchange and integration. The specification covers how to represent coded values in FHIR resources, binding strengths for value sets, and integration with major terminologies like SNOMED CT, LOINC, ICD, and RxNorm for standardizing both structured and unstructured health data. Terminology Open access HDB-0482

ICD-10-CM and ICD-10-PCS

Centers for Disease Control and Prevention (CDC) / Centers for Medicare & Medicaid Services (CMS) ICD-10-CM (Clinical Modification) is the US diagnostic coding system maintained by CDC for classifying diagnoses and reasons for visits in all healthcare settings, while ICD-10-PCS (Procedure Coding System) is the inpatient procedure coding system maintained by CMS. Both replace their ICD-9 predecessors and are the official coding standards for U.S. healthcare billing and reporting. Terminology Open access HDB-0483

NDC National Drug Code Directory

Food and Drug Administration (FDA) The NDC (National Drug Code) Directory is the FDA's official database containing information on active finished and unfinished drugs submitted in structured product labeling files by drug manufacturers. It includes the three-segment NDC number that identifies each drug product and is updated daily with prescription, over-the-counter, approved, unapproved, repackaged, relabeled, and compounded drug products. Terminology Open access HDB-0485

Human Phenotype Ontology

The Jackson Laboratory A standardized vocabulary of phenotypic abnormalities and clinical findings in human disease. Maintained by the Monarch Initiative and widely used for clinical annotation, genetic diagnosis, and rare disease research. Terminology Open access HDB-0486

Gene Ontology

The Gene Ontology Consortium The world's source of structured information on gene functions across molecular, cellular, and organismal levels, with standardized terms for describing gene products. Freely available for browsing, searching, downloading, and API access with support from the National Human Genome Research Institute. Terminology Open access HDB-0487

HGNC (Hugo Gene Nomenclature Committee)

HUGO Gene Nomenclature Committee The authoritative resource for approved human gene nomenclature and symbols, maintained as the international standard for official gene names. All data files and archives are freely available in a publicly accessible repository. Terminology Open access HDB-0488

ChEBI (Chemical Entities of Biological Interest)

EMBL-EBI (European Bioinformatics Institute) An open-access database and ontology of chemical entities used in biological research, ions, and complexes. Each entry includes chemical nomenclature following IUPAC standards, literature citations, and cross-references to other databases. Terminology Open access HDB-0489

Disease Ontology

Institute for Genome Sciences, University of Maryland A, semantically-structured ontology organizing disease knowledge through etiology-based classification and providing searchable disease terminology. Recognized as a Global Core Biodata Resource with monthly releases of OBO, OWL, and JSON ontology files available freely through GitHub. Terminology Open access HDB-0490

Mondo Disease Ontology

Monarch Initiative A unified disease terminology system that harmonizes disease definitions across the world by merging multiple disease resources into one coherent ontology. Contains disease concepts with precise mappings between different medical databases and is released under CC-BY 4.0. Terminology Open access HDB-0491

NCI Thesaurus

National Cancer Institute A cancer research terminology system developed by the National Cancer Institute as part of the Enterprise Vocabulary Services. Provides standardized terminology for oncology research, clinical trials, and cancer informatics applications. Terminology Open access HDB-0492

UCUM (Unified Code for Units of Measure)

Regenstrief Institute and UCUM Organization A code system enabling unambiguous electronic communication of measurements and their associated units across international science, engineering, and business. Adopted by major organizations including IEEE, DICOM, LOINC, and HL7, and incorporated into ISO 11240:2012 standard. Terminology Open access HDB-0494

TNM Classification of Malignant Tumours

Union for International Cancer Control (UICC) A globally recognized standard for classifying the extent of cancer spread using T (primary tumor), N (lymph node involvement), and M (metastatic spread) components. Maintained by UICC for years with the 9th edition (2025) published through Wiley, with free educational materials available. Terminology Paid HDB-0533

OMIM (Online Mendelian Inheritance in Man)

Johns Hopkins University OMIM (Online Mendelian Inheritance in Man) is a catalogue of human genes and genetic phenotypes, focused on Mendelian disorders and the relationships between genes and disease. It is authored and edited at the McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, is updated daily, and is free to browse with registration required for bulk downloads. Terminology Free registration HDB-0534

Orphanet (Rare Disease Database)

INSERM (Institut National de la Santé et de la Recherche Médicale), France Orphanet is a reference portal on rare diseases and orphan drugs, maintaining an inventory and classification of rare diseases together with the ORPHAcode nomenclature, directories of expert centres, diagnostic tests and patient organisations. It was established by INSERM in France in 1997 and is now run by a consortium of partner countries; the website is free to use and bulk datasets are published through Orphadata. Terminology Open access HDB-0535

CPT (Current Procedural Terminology)

American Medical Association (AMA) CPT is the standardized procedural coding system maintained by the AMA that describes medical, surgical, and diagnostic services and procedures performed by healthcare providers. CPT codes are widely used for billing and reimbursement under public and private insurance programs in the United States and are updated annually to reflect current clinical practice and medical innovation. Terminology Paid