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Unified Medical Language System (UMLS)

UMLS Vocabularies

CDT (CDT) - Source Representation


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

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Summary of Changes
Summary of Source-Provided Files
Source-Provided File Details

Summary of Changes:

There were no changes to the original file format. Minor changes were made to the assignment of CODE and SCUI values of atoms with TTY = "HT"

Notes:

  • In the printed CDT book, some codes appear out of order. The order information is not available in electronic form, therefore the UMLS hierarchy varies slightly from the hierarchy in the printed book.
  • A value of "None" in the original data is treated the same as a blank or null value.

CDT in the Metathesaurus is extracted from a file provided by the American Dental Association (ADA). The Metathesaurus also includes the HCPCS version of CDT, which has RSAB = "HCDT." The CDT hierarchy is created from the data file provided by the ADA, while the HCDT hierarchy is created during Metathesaurus production using analysis of the HCPCS printed manual.

Source-Provided Files: Summary

File Name Description
CDT 2023 ASCII Tab Delimited_2022May17.txt Documentation and tab delimited text file (the data is also available from the ADA as an Excel file)
ReadMe_CDT 2023_6.3.22.pdf Documentation

Source-Provided Files: Details

The following is a list of elements in the CDT source file:

Element Representation
Code MRCONSO.CODE
MRCONSO.SCUI
Class MRSAT.ATN = CHANGE_CLASS

Identifies the type of change made to this version of the Code (i.e., changes from the prior version), with the following meanings:
  • 30 = No change to existing code, nomenclature or descriptor
  • 31 = New procedure code and nomenclature, and descriptor, if present
  • 35 = Revision in the nomenclature or descriptor (or both), or to indicate a revision to an entire subcategory
  • 39 = Editorial (e.g., syntax; spelling)
  • 99 = Entire CDT Code entry is no longer valid (i.e., deleted) in this version.
Nomenclature MRCONSO.STR
MRCONSO.TTY = PT unless Class = 99
MRCONSO.TTY = OP if Class = 99
MRCONSO.CODE = Code value
MRCONSO.SDUI = same as CODE
Descriptor MRSAT.ATN = SOS
Class2 Not processed; ambiguous as to whether this field refers to the category, subcategory or subsubcategory
Category MRCONSO.STR
MRCONSO.TTY = HT
MRCONSO.CODE = computed based on the range of codes included under this Category
MRCONSO.SCUI = same as CODE
CatDescriptor MRSAT.ATN = SOS
Subcat MRCONSO.STR
MRCONSO.TTY = HT
MRCONSO.CODE = computed based on the range of codes included under this Subcategory
MRCONSO.SCUI = same as CODE

Values of "None" are processed the same as null/blank values.
SubcatDescriptor MRSAT.ATN = SOS
Subsubcat MRCONSO.STR
MRCONSO.TTY = HT
MRCONSO.CODE = computed based on the range of codes included under this Subsubcategory
MRCONSO.SCUI = same as CODE

Values of "None" are processed the same as null/blank values.
SubsubcatDescriptor MRSAT.ATN = SOS

In the case where the Subsubcat value = "None" but the SubsubcatDescriptor is populated, the SubsubcatDescriptor is considered an additional SOS for the Subcat.