---
type: "operations"
title: "CodeSystem Operations"
resource: "CodeSystem"
---
# CodeSystem Operations

- [lookup](/codesystem-operation-lookup) — Concept Look Up & Decomposition — Given a code/system, or a Coding, get additional details about the concept, including definition, status, designations, and properties.
- [subsumes](/codesystem-operation-subsumes) — Subsumption Testing — Test the subsumption relationship between code/Coding A and code/Coding B given the semantics of subsumption in the underlying code system (see [hierarchyMeaning](codesystem-definitions.html#CodeSystem.hierarchyMeaning)).
- [validate-code](/codesystem-operation-validate-code) — Code System based Validation — Validate that a coded value is in the code system.