The official version of the OHIE workflows can be found in the OpenHIE Architecture Specification.


Description: This transaction allows a PoS, or any OHIE component, to access terminological information in the terminology service to verify that a code exists in a Code System.  A typical example would be to validate that the codes contained in an incoming patient data message are, in fact, from a required code system, e.g. ICD-10 or LOINC.

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. Existence: Is a Concept Code present in a specified Code System. E,g., is '123XYZ' a valid Code in the ICD-10 Code System?

Sponsor:  Jack Bowie

Status:  This operation has been extensively tested in FHIR Connectathons. 

Referenced Standards and APIs

Assumptions and Prerequisites


title Verify Code Existence 
participant PoS
participant TS

PoS->TS: [1] Code verification request
TS->PoS: [2] Code verification response 

Technical details

Below enter each interaction that makes up the described workflow above.

RefInteractionEndpointDataTransaction Specification
1Code verification requestTS

The validate-code request is triggered by a PoS or other HIE component.

Input: A Concept Code and target Code System.

FHIR CodeSystem Resource, $validate-code operation
2.Code verification responsePoSThe response is sent back to the requesting system. Output: a True or False response. FHIR CodeSystem Resource, $validate-code operation