Query Code Systems

This transaction allows a PoS, or any OHIE component, to access terminological information in the terminology service to query for Code Systems. A typical example would be to request the set of Code Systems defined by HL7.

Both external systems and systems inside the HIE may perform this transaction directly with the TS. The sequence diagram below shows the steps that occur for a system using this transaction.

  1. Query Code Systems: What Code Systems have a publisher name that contains 'HL7'?

Workflow Maturity


  • One or more OpenHIE implementations of this workflow exist in one or more countries

  • Workflow is defined and ARB approved

  • Workflow is supported by mature standards


The FHIR Code Systems and supported search parameters are defined in: https://www.hl7.org/fhir/codesystem.html. Searching in FHIR is described in https://www.hl7.org/fhir/search.html. HL7 FHIR Specifications v3.0 or higher support Code Systems. The response is a Bundle of CodeSystem Resources satisfying the search parameters.

This workflow implements the IHE IT Infrastructure Technical Framework Supplement - Sharing Valuesets, Codes, and Maps (SVCM) Transaction: Query Code System ITI-Y2.

Assumptions and Prerequisites

The required Code Systems have been preloaded into the Terminology Service.


  • PoS - The point-of-service system or other HIE component that is that is querying for Code Systems.

  • TS - Stores the curated, official version of the Code Systems for the health system.

Interaction Description

The following is a description of the interaction steps.




Transaction Options


Query Code System request

The Code System search request is triggered by a PoS or other HIE component.

Input: A set of FHIR search parameters.

FHIR CodeSystem Resource


Query Code System request

The response is sent back to the requesting system.

Output: a Bundle of CodeSystem Resources that satisfy the search parameters.

FHIR CodeSystem Resource

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