Da Vinci Clinical Data Exchange (CDex)
1.1.0 - STU1.1 US

This page is part of the Da Vinci Clinical Documentation Exchange (v1.1.0: STU1.1) based on FHIR R4. This is the current published version in its permanent home (it will always be available at this URL). For a full list of available versions, see the Directory of published versions


Official URL: http://hl7.org/fhir/us/davinci-cdex/ImplementationGuide/hl7.fhir.us.davinci-cdex Version: 1.1.0
Active as of 2022-08-10 Computable Name: DaVinciCDex

Copyright/Legal: Used by permission of HL7 International all rights reserved Creative Commons License

The attachment transaction and purpose of use content is DRAFT. It has not yet undergone HL7 balloting. The appropriate pages and sections are preceded with an STU-Note indicating the draft content.

This IG provides detailed guidance that helps implementers use FHIR-based interactions to support specific exchanges of clinical data between providers and payers (or other providers). This guide documents the Direct Query, Task Based and Attachments transaction approaches for requesting and sending information. Key scenarios this IG can support include:

  • Requesting and Sending attachments for claims and prior authorization
  • Requesting documentation to support payer operations such as claims audits
  • Gathering information for Quality programs and Risk Adjustment between payers and providers
  • Exchanging clinical data between referring providers

In the context of this guide, “clinical data” means any information a provider holds in a patient’s health record. The format of the data exchanged is not limited to FHIR resources but includes C-CDA documents, PDFs, text files, and other types of data. There may be requests for payloads of clinical records of care such as CCD Documents, clinical data sets that may be represented in a FHIR Bundle (or C-CDA on FHIR Documents), and clinical data such as a specific FHIR resource.

By using the FHIR standard and implementing this guide, payers can be explicit about the data they are requesting as opposed to general requests which often result in providers sending more information than is necessary. The anticipated benefit of using FHIR is a more efficient and effective exchange of health record information in several areas such as claims management, care coordination, risk adjustment, and quality reporting.

This IG provides several generic examples to illustrate the different approaches for exchanging clinical data when using the Direct Query and Task-Based approaches. It also documents and provide examples for the specific use case of requesting and sending attachments for claims and prior authorization. We plan to create a set of Clinical Data Exchange- Supplemental Guides which will document and provide examples for other specific use cases.

About This Guide

This Implementation Guide is supported by the Da Vinci initiative which is a private effort to accelerate the adoption of Health Level Seven International Fast Healthcare Interoperability Resources (HL7® FHIR®) as the standard to support and integrate value-based care (VBC) data exchange across communities. Like all Da Vinci Implementation Guides, it follows the HL7 Da Vinci Guiding Principles for the exchange of patient health information. The guide is based upon the prior work from the US Core and Da Vinci Health Record Exchange (HRex) Implementation Guides. For general Background on FHIR and Conformance Expectations, refer to the corresponding sections in the Da Vinci Health Record Exchange (HRex) Implementation Guide. For Security and Privacy considerations refer to the Security and Privacy page. As illustrated in figure 1 below, this guide is built on top of FHIR and other implementation guides that provide more and more focused use cases by constraining profiles and extending functionality to cover gaps. For Direct Query and Task-based queries, US Core and HRex define the content that is exchanged, while CDex defines additional conditions for how it is exchanged. For Attachments, CDex defines both new content and how it is exchanged.

Figure 1: Relationship of CDex to Other FHIR Standards

Changes to this specification are managed by the sponsoring HL7 Patient Care workgroup and are incorporated as part of the standard HL7 balloting process. You can suggest changes to this specification by creating a change request tracker by clicking on the Propose a Change link at the bottom of any page.

How to read this Guide

In this guide several terms are used to denote the actors and their roles in CDex transactions:

Data Consumer
The term “Data Consumer” is used to mean both payer and provider systems when they are requesting data.
Data Source
The term “Data Source” or “Data Source(HIT)” or “HIT system” is used to mean the source of data, which could be an EHR, HIM, Practice Management System, Population Health, Registration, or other HIT that may have support information or other data elements.
The term “Data Consumer(Payer)” or “Payer” is used when only the payer system (or an intermediary on behalf of a payer) is requesting data.
The term “Provider” is used to mean the provider system and can be either the Data Source or the Data Consumer.
The term “Attachments” is limited to a subset of additional information that are documents defined by the LOINC Document Ontology or data elements that are presented in document form.

This Guide is divided into several pages which are listed at the top of each page in the menu bar.

  • Home: The home page provides the introduction to the Da Vinci Clinical Data Exchange Project.
  • Background: This page provides the background and a summary of the Da Vinci Clinical Data Exchange Project.
  • Direct Query: Documents how to exchange clinical data using the standard FHIR RESTful search.
  • Task Based Approach: Documents how to exchange clinical data using the FHIR Task resource. This approach supports asynchronous workflows where human involvement to find/aggregate/filter/approve requests may be required.
  • Attachments: This content is DRAFT and is open for review. Documents how to exchange attachments for claims or prior authorization.
    • Solicited and Unsolicited Attachments: Documents the differences and similarities between solicited and unsolicited attachments workflows and the CDex transactions that can be used for each.
    • Sending Attachments:This page documents a FHIR based approach for sending attachments for claims or prior authorization directly to a Payer.
    • Requesting Attachments: This page documents a FHIR based approach for requesting attachments for claims or prior authorization from a Provider.
    • Using CDex Attachments with DaVinci PAS: This page illustrate where in the PAS workflow the Payer could use CDEX to request attachments and the Provider could use CDEX to submit attachments.
  • Signatures: This page provides specific guidance and rules to exchange signed data using FHIR and non-FHIR signatures.
  • Security and Privacy: This page provides general expectations to ensure the security, privacy, and safety of Da Vinci CDex exchanges.
  • FHIR Artifacts: This page list the FHIR Profiles, Operations, Terminology, CapabilityStatements, and example resources used within this guide.
  • Downloads: This page provides links to downloadable artifacts that can be used by developers to help them implement this guide.
  • Change Log: This page documents the changes across the versions of CDex

This Implementation Guide was made possible by the contributions of the Da Vinci Project member organizations and project management staff, the Patient Care Work Group, and the Payer/Provider Information Exchange Work Group.


  • Eric Haas, Health eData Inc
  • Lloyd Mckenzie, Gevity Consulting
  • Robert Dieterle, EnableCare