Manipulate SNOMED CT Diagnosis Lists R package Rdiagnosislist version 1.5.1 Functions and methods for manipulating 'SNOMED CT' concepts. The package contains functions for loading the 'SNOMED CT' release into a convenient R environment, selecting 'SNOMED CT' concepts using regular expressions, and navigating the 'SNOMED CT' ontology. It provides the 'SNOMEDconcept' S3 class for a vector of 'SNOMED CT' concepts (stored as 64-bit integers) and the 'SNOMEDcodelist' S3 class for a table of concepts IDs with descriptions. The package can be used to construct sets of 'SNOMED CT' concepts for research (<doi:10.1093/jamia/ocac158>). For more information about 'SNOMED CT' visit <https://www.snomed.org/>. Software Depends: readxl, R (>= 3.5.0) Imports: data.table (>= 1.12.8), bit64, methods Suggests: knitr, rmarkdown, testthat Anoop D. Shah <anoop@doctors.org.uk> Comprehensive R Archive Network (CRAN) Anoop D. Shah [aut, cre] (ORCID: <https://orcid.org/0000-0002-8907-5724>) GPL-3 2026-06-24 application/tgz https://CRAN.R-project.org/package=Rdiagnosislist doi:10.32614/CRAN.package.Rdiagnosislist