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

IG Conformance

This page defines how Logical Models are structured and the expectations for elements CREDS profiles. It provides guidance on how a system may support the StructureDefinitions as profiled by CREDS to represent data requirements for registries.

Note: the key words “MUST”, “MUST NOT”, “SHALL”, “SHALL NOT”, “SHOULD”,”SHOULD NOT”, “MAY”, and “OPTIONAL” in this IG are to be interpreted as described in IETF BCP 14.

Conformance Artifacts

The Profiles and Extensions page lists the FHIR resource profiles as used in this Implementation Guide.

The Profile elements consist of both Mandatory and Must Support elements. Mandatory elements are elements with an minimum cardinality of 1 (min=1). The sections below illustrate how these elements are displayed and define the rules for interpreting profile elements and sub-elements labeled Mandatory and Must Support for requesters and responders.

This Implementation Guide follows US Core requirements for Must Support elements

Logical Model Requirements

Each Repository’s data requirements are expressed as a FHIR Logical Models using a CREDSStructureDefinition. Each of these models will create a structure as a Profile of CREDSStructureDefinition. This profile is what will be given to a Registry Submitter to use as a map to fetch and compile the data.

Each Logical Model will follow this basic structure: Publisher information: The following elements MUST be populated

  • date: publishing date of the current version
  • publisher: The organization publishing the data requirements
  • Name of the primary contact for questions regarding the data map
  • contact.telecom.system: either email and/or telephone

Core Map Information The mapping elements MUST be populated as follows: Output: location where data is entered into a resource or profile for inclusion into the Submission Bundle

mapping.identity MUST be "Output"
mapping.uri MUST be "" MUST be "Submission Data Output location"

Each of the other mapping entries are OPTIONAL unless mapping to that standard. If FHIR mapping is used in any mapping element, the following MUST be included in the root of the CREDSStructureDefinition:

mapping.identity = "FHIR"
mapping.uri = "" = "Fast Health Interoperability Resources"

If CDA mapping is used in any mapping element, the following MUST be included in the root of the CREDSStructureDefinition:

mapping.identity = "CDA"
mapping.uri = "" = "Clinical Document Architecture"

If HL7 V2 message mapping is used in any mapping element, the following MUST be included in the root of the CREDSStructureDefinition:

mapping.identity = "HL7V2"
mapping.uri = "" = "HL7 V2 Messages"

Mapping Elements

Each data point in the Registry data map corresponds to an element in the logical model. Elements may be categorized through the use of a BackboneElement which holds no value. Each data point is named with a camelCase version of a short data point name without whitespace or punctuation.

Each element has a base definition of cardinality (how many of that element there can be) a short name and a full definition. The definition may give guidance on the data point’s formatting or other requirements. The element also gives specifics on the source mapping (i.e., where the data can be found)in zero or more standards-based formats (e.g., FHIR, CDA). If no “Source Standard” mappings are supplied, it should be assumed that the data is only available through a manual process.

Each mapping MUST contain the following elements:

mapping.identity: the "Source Standard" such as FHIR, CDA, HL7V2
mapping.language the mimetype of standard (e.g., application/fhir, application/hl7-sda+xml [CDA], application/edi-hl7v2 [HL7 V2]) the FHIRPath to to be used as a query for the data 

In addition to the source mapping, the destination element (Output) is structured the same as a FHIR Source Standard element that has the mapping point to the full path to the FHIR resource or Profile that will be used in the submission Bundle.

mapping.identity: MUST be Output
mapping.language: MUST be application/fhir the resource name (e.g., Observation) or the full path to the destination profile (e.g., for the USCore Patient profile) may have requirements for specific elements appended in FHIRPath e.g., .where([element] = [value]) or have ValueSet requirements for response (e.g., Observation.valueCodeableConcept.code.memberOf([ValueSet])). Where a ValueSet is appended, responses must be a selection from that ValueSet. This should only be specified for manual response entry.

Requirements for the Output resources are shown as .where() requirements. If a certain element requires a specific value, that is shown as equivalence. WHere choices are needed from a value set, those are shown as .memberOf(); this is most often with Manual entry requirements. If the manual value entered is of a certain type, that will be shown as .exists()

e.g., Observation.where(code.coding.system='' and code.coding.code=89440-2 and component.code.memberOf(RoseDyspneaQ) and component.valueCodeableConcept.memberOf(YesNo))
Observation.where( code.coding.system='' and code.coding.code=10001424782 and valueBoolean.exists())

If an element has a minimum requirement, i.e., minimum cardinality of 1 then Data Absent Reason must be supplied via a resource element or via the Data Absent Reason Extension if no response is available due to query failure and manual prompt gives no response.

Query ValueSet Binding

Where needed, a Logical Model may have a binding to one or more ValueSets that outline the codes needed for a query. For example, a bound ValueSet with list of CPT, SNOMED and/or LOINC, etc. codes that would match a needed condition could be used to tightly specify a query. This may allow for better targeted queries from the Submitter to its sources. This can be specified best using the FHIRPath function memberOf() in the FHIR mapping.

Submission Bundle

The CREDS submission bundle is a FHIR Bundle of type “Collection”.

  • The first entry in the Bundle MUST be a MessageHeader indicating who is submitting this data
  • The second entry MUST be the US Core Patient resource for the subject of the submission.

All other entries are dictated by the Registry data dictionary.

When using the CREDS submission bundle, the Resources for all Data Dictionary elements should have the element(s) path as a tag within the Resource .meta.tag elements. This will allow the Registry to better map the Bundle entries back to the data dictionary. As example:

 "tag": [
      "system": "",
      "value": "discharge.discharge.datetime"
      "system": "",
      "value": "discharge.dischargeProvider
      "system": "",
      "value": "discharge.discharge.location"

This would be the entries for location, date and time and the provider within the Discharge encounter.

Submission Response

A Submission using CREDS can have different result sets. Using a single Bundle submission should receive a 201 Immediately with a CREDSOperationOutcome attached immediately. Where the system is unable to respond to the validation in within a timeout requirement, following the ASync Bulk Pattern.

Where Submissions have been in bulk, a response of 202 Accepted should be returned if the Bundle is valid NDJSON with the URL for status requests. Once the processing and validation is complete, a Bundle of CREDSOperationOutcomes should be placed, in NDJSON format at the status url for pickup.