Protocols for Clinical Registry Extraction and Data Submission (CREDS) IG
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Protocols for Clinical Registry Extraction and Data Submission (CREDS) IG, published by HL7 International / Clinical Interoperability Council. This is not an authorized publication; it is the continuous build for version 1.0.0. This version is based on the current content of and changes regularly. See the Directory of published versions


This guide uses structures that define the report in steps from the base profile on StructureDefinition, to the Logical Model that defines the information requirements, to the final StructureDefinition that outlays the individual record and the mappings to the final bundle required.

Major Components

The major design components described by this guide support the following functions:

  1. Definition - gives an overall structure and requirements with references to major standards (FHIR, CDA, V2) and the relevant FHIR Profile (such as USCore Patient or International Patient Summary Patient) for final submission.
  2. Retrieval - fetching the data from the listed sources or from non-automated locations requiring human intervention
  3. Submission creation - Entering patient data in the elements in the FHIR Resources and/or profiles that will comprise the submission Bundle.
  4. Submission - use of a base CREDSBundle or other FHIR IGs such as UDS+ or MedMorph for submission of the resulting Bundle.

The first four functions are described in more detail in the sections below.


The Registry Submission Definition Creator executes the Create/Update Registry Definition [CURD] transaction and uses a tool to create a logical model in the form of a StructureDefinition that references the data needed, the possible locations in FHIR, CDA or other locations, including manual input, and the local profile necessary to store the information for submission.

The overall StructureDefinition will have each datapoint as an element definition with mappings to the data locations and the resource or profile for storage within the submission Bundle.

This information is given to the Registry Submission Definition Repository for storage and distribution.


Fetch patient fromRegistry worklistFetch FHIR data fromthe data sourceIdentify theData SourceFHIR API requestto get the dataadditionalFHIR Data?Fetch Non-FHIR datafrom other sourcesIdentify the data sourceUse other methodsto get the dataadditionalNon-FHIR Data?UI to Complete Review DataCapture additional dataavailable through automationReview and Sign the RecordAdditionalFHIR Data?Locally Aggregate andTransmit data to Registry
Workflow for Retrieval and Submission

The Registry Submitter uses the Search/Retrieve Registry Definition [SRRD] transaction to find and retrieve the appropriate definition from the Repository,

Once the definition has been ingested, the Registry Submitter or the Registry Submission Data Source fetches the required data (the Retrieve Registry Submission Data [RRSD] transaction) from those locations in the mappings within the StructureDefinition logical model or from appropriate locations within the EHR or other relevant system.

Submission Creation

The Registry Submitter executes the Create / Update Registry Submission [CURS] transaction, placing the data in the relevant resources/profiles and assembling the CREDSSubmission Bundle or other FHIR IG mandated Bundle for submission.

Alternately, the Registry Submission Consumer may work with individual datapoints in the Registry Definition and assemble the Submission itself, rather than relying on an external actor.

The actor then Validate Registry Submission [VRS] through automatic and/or manual process as defined by organization policy to ensure completeness and correctness.


This may fall outside of this IG, if using MedMorph or another IG for submission requirements.

If not, then submission may use the following structure:

<Bundle xmlns="">
<!--CREDSSubmission metadata here, type MUST be collection -->
<!--First entry is MessageHeader with Submitter Information -->
<!--Second entry is Patient Resource -->
<!--Other entries with clinical data -->

Submission responses may return only an http success code or may return a OperationOutcome resource depending on the needs of the submitter and registry and/or the requirements of the FHIR IG used for submission.

Submissions can be done on-demand by event-driving immediate submission or via a periodic submission. Periodic (bulk) submissions can be managed by one of three ways:

  1. a Bundle of type transaction comprised of Submission Bundles. The receiver will accept or reject this Bundle of Bundles in total if one or more of the CREDSSubmission Bundles is or is not accepted.
  2. a Bundle of type batch comprised of Submission Bundles. The receiver will only reject individual CREDSSubmission Bundle entries within the Bundle of Bundles
  3. Asynchronous submission of NDJSON files of Submission Bundles. This uses the $registryUpload Operation attaching the data to a Binary resource as an NDJSON file of individual CREDSSubmission Bundles. This use the Asynchronous FHIR with a 202 Accepted response with the Content-Location parameter holding the polling location for the NDJSON file of OperationOutcome resources for each line of the submission file.

The first two options are sufficient for low numbers of CREDSSubmission Bundles. For larger periodic submissions (hundreds or thousands of submissions), option 3 is optimal. All three can be managed using Asynchronous FHIR or via immediate response.

All three will result in OperationOutcome resources, outlining the accepting or rejecting of the individual submissions. Option 1 or 2 would result in a Bundle of type transaction-response or batch-response containing the OperationOutcomes, option 3 would create an NDJSON file of the OperationOutcome resources that would be polled for and retrieved.

An example flow for Option 3 would be as follows:

SubmitterSubmitterRegistryRegistryUpload NDJSON file of recordsPOST$registryUpload?_format=application/fhir+ndjson HTTP/1.1Host:example.orgPrefer: respond-asyncAccept: application/fhir+ndjson{"resourceType": "Binary","id": "example","contentType": "application/fhir-ndjson","data": "[NDJSON File of CREDSBundles in base64 format]"}202 AcceptContent-Location: AcceptOptionally an X-Progress header with atext description of the status of the request that'sless than 100 charactersWhen processing completeGET Successsee details of response
Example Async Submission Flow

It is suggested that if Option 3 is chosen, that the uploads be done in smaller sections within multiple files to allow for easier management of the upload (i.e., parallelism, re-uploading) and to prevent having to re-upload large files in the case of an upload transmission error.