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Unified Medical Language System (UMLS)

UMLS Vocabularies

MED-RT (Medication Reference Terminology) - Metathesaurus Representation

This page lists UMLS Metathesaurus data elements and traces them back to the specific source data that populates them.

VSAB: MED-RT_2022_03_07

Summary of Changes

There have been no changes to the MED-RT release format or Metathesaurus source processing.

Source Provided Files:

All source files, including documentation, are available on the MED-RT download site:

File Description
Core_MEDRT_YYYY.MM.DD_XML.xml Data file
MED-RT Documentation.pdf Documentation
MED-RT_Schema_v1.xsd XML schema definition


Identifiers are assigned as follows:
  • CODE: <Concept><Code> (same as NUI property)
  • SAUI: not applicable
  • SCUI: Same as CODE
  • SDUI: not applicable

Atoms (MRCONSO):

Term Type Origin
FN CODE, SCUI: <Concept><Code> (same as NUI property)
STRING: <Concept><Name>
PT CODE, SCUI: <Concept><Code> (same as NUI property)
<Concept><Property><Synonym><to_name> where <name> = "Preferred Term" and <preferred> = "true"
SY CODE, SCUI: <Concept><Code> (same as NUI property)
<Concept><Property><Synonym><to_name> where <name> = "Synonym" and <preferred> = "false"

Attributes (MRSAT):

Attribute Name Origin Notes
AUTHORITY <association><qualifier><name> = Authority MRSAT.STYPE = RUI
Identifies the authoritative source(s) for a relationship. Conflicting relationships from different authorities can coexist in the knowledge base. Valid relationship source authorities are:
  • MEDRT - relationship asserted by legacy NDF-RT subject matter experts or by MED-RT
  • FMTSME - relationship recommended by FMT subject matter experts for SPL
  • FDASPL - relationship assigned by FDA SPL to active ingredient moieties
  • NLMUMLS - relationships from RxNorm ingredients to MeSH structural classes as defined by the UMLS Metathesaurus
CONCEPT_TYPE <property><name> = CTY Concept type: a category or label assigned only to every concept owned by MED-RT. Valid CTY values include:
  • EPC - FDA SPL established pharmacologic class
  • APC - additional pharmacologic class
  • MoA - mechanism of action
  • PE - physiologic effect
  • TC - therapeutic category
  • PK - pharmacokinetics
  • EXT - local terminology extensions
  • HC - local hierarchical concept to aggregate subconcepts, alphabetically or conceptually
TERM_STATUS <concept><status> Always "A" (approved)

Definitions (MRDEF):

No definitions are included in the MED-RT data.

Relationships (MRREL):

Inverse RELA
Origin Description Target concept terminology or CTY
parent_of/has_parent <association><name> = Parent of Hierarchical or taxonomic parent of concept. PAR/CHD relationships between two MED-RT concepts are also represented in MRHIER.RRF CTY: same CTY as concept of origin (e.g., MoA, PE, EPC, PK, TC, EXT) if MED-RT target, or Target: SNOMED CT US Edition or MeSH if mapped into external terminology hierarchy
RO contraindicated_class_of
<association><name> = CI_ChemClass Chemical structural class of a co-administered ingredient MeSH
RO contraindicated_mechanism_of_action_of
<association><name> = CI_MoA Contraindicated mechanism of action of a co-administered ingredient CTY: MoA
RO contraindicated_physiologic_effect_of
<association><name> = CI_PE Contraindicated physiological effect of a co-administered ingredient CTY: PE
RO contraindicated_with_disease
<association><name> = CI_with Therapeutic or co-morbid contraindication of an ingredient MeSH
RO effect_may_be_inhibited_by
<association><name> = effect_may_be_inhibited_by An ingredient interfering with therapeutic effect of an ingredient MeSH
RO has_active_metabolites
<association><name> = has_active_metabolites Chemically-active metabolic product of an ingredient MeSH
RO has_mechanism_of_action
<association><name> = has_MoA Molecular, subcellular, or cellular level functional activity of an ingredient CTY: MoA
RO has_pharmacokinetics
<association><name> = has_PK Absorption, distribution, and elimination of an ingredient CTY: PK
RO has_physiologic_effect
<association><name> = has_PE Tissue, organ, or organ system level functional activity of an ingredient CTY: PE
RO has_structural_class
<association><name> = has_SC Structural classification mapping of an ingredient MeSH
RO has_therapeutic_class
<association><name> = has_TC Therapeutic intent categorization of an ingredient CTY: TC
RO induces
<association><name> = induces Therapeutic effect or state caused by an ingredient MeSH
RO may_diagnose
<association><name> = may_diagnose Diagnostic use or indication of an ingredient MeSH
RO may_prevent
<association><name> = may_prevent Preventative use or indication of an ingredient MeSH
RO may_treat
<association><name> = may_treat Therapeutic use or indication of an ingredient MeSH
RO site_of_metabolism
<association><name> = site_of_metabolism Metabolic anatomic site of an ingredient CTY: PK
SY <association><name> = Synonym Of mapped equivalent or synonymous concept in external terminology hierarchy SNOMED CT US Edition or MeSH

Mappings (MRSMAP, MRMAP):

There are no MRSMAP.RRF or MRMAP.RRF entries for MED-RT, however MRREL.RRF includes relationships between MED-RT and other sources.