Da Vinci Clinical Data Exchange (CDex)
2.1.0-preview - CI Build United States of America flag

Da Vinci Clinical Data Exchange (CDex), published by HL7 International / Payer/Provider Information Exchange Work Group. This guide is not an authorized publication; it is the continuous build for version 2.1.0-preview built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/HL7/davinci-ecdx/ and changes regularly. See the Directory of published versions


Official URL: http://hl7.org/fhir/us/davinci-cdex/ImplementationGuide/hl7.fhir.us.davinci-cdex Version: 2.1.0-preview
IG Standards status: Trial-use Maturity Level: 2 Computable Name: DaVinciCDex
Other Identifiers: OID:2.16.840.1.113883.4.642.40.21

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


This IG provides detailed guidance that helps implementers use FHIR-based interactions to support specific clinical data exchanges 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. In addition to requesting FHIR resources, there can Implementers can request clinical records of care such as CCD Documents or C-CDA on FHIR Documents, or clinical data sets represented by a FHIR Bundle, a FHIR QuestionnaireResponse, or other types of FHIR resources.

By using the FHIR standard and implementing this guide, payers can be explicit about the data they are requesting instead of general requests, which avoids sending more information than necessary. As a result, 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 using Direct Query and Task-Based transactions. It also documents and provides examples for Requesting and Sending Attachments for claims and prior authorization. In addition, 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

The Da Vinci initiative supports this implementation guide. Da Vinci 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. This guide adheres to the HL7 Da Vinci Guiding Principles for the exchange of patient health information.

As illustrated in Figure 1 below, this version of CDex is based on FHIR R4, and much of its content is dependent upon the [Da Vinci Health Record Exchange (HRex), US Core 3.1.1 (FHIR R4), and US Core 6.1.0 (FHIR R4) implementation guides. For general Background on FHIR, Conformance Expectations, and Security and Privacy considerations, refer to the corresponding sections in HRex. US Core 3.1 meets regulatory requirements mandating support for ONC United States Core Data for Interoperability V1 (USCDI V1), and US Core 6.1.0 meets regulatory requirements mandating support for ONC United States Core Data for Interoperability V3 (USCDI V3)]. For Direct Query and Task-Based queries, US Core and HRex define the underlying content, and CDex provides additional context, definitions, and constraints. CDex provides more focused use cases by constraining profiles and extending functionality to cover gaps. For example, CDex defines all the content for Attachments.

Figure 1: Relationship of CDex to Other FHIR Standards

The sponsoring HL7 Patient Care workgroup manages changes to this specification. Changes 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

This guide uses the following terms to document the 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”, “Data Source(HIT)”, or “HIT system” refers to an EHR, HIM, Practice Management System, Population Health, Registration, or other systems that stores the data and responds to data requests.
“Data Consumer(Payer)” or “Payer” refers to the payer system (or an intermediary on behalf of a payer) and is used when they are requesting data.
“Provider” refers to the provider system and can be either the Data Source or the Data Consumer.
This guide uses the terms “attachments”, “additional information”, and “attachments and additional information” to mean additional information needed for claims and prior authorization. Attachments are limited to the documents defined by the LOINC Document Ontology and X12 in the context of requesting and sending attachments using attachment codes. When requesting and sending attachments using Questionnaire, attachments mean any additional information.

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

  • Home: The home page introduces the Da Vinci Clinical Data Exchange Project and Implementation Guide.
  • 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 exchanging clinical data using the FHIR Task resource. This approach supports asynchronous workflows and may require human involvement.
  • Attachments: Documents exchanging attachments for claims or prior authorization using FHIR.
  • 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 lists the FHIR Profiles, Operations, Terminology, CapabilityStatements, and example resources used within this guide.
  • Downloads: This page provides links to downloadable artifacts that developers can use 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

CDex Core Team:

  • Lloyd Mckenzie, Accenture/Dogwood Health Consulting
  • Robert Dieterle, EnableCare
  • Christol Green, Elevance Health
  • Durwin Day, - Health Care Service Corporation

Project Management and Coordination:

  • Viet Nguyen, Stratametrics, LLC
  • Vanessa Candelora, Point of Care Partners
  • Crystal Kallem, Point of Care Partners
  • Yan Heras, Optimum eHealth LLC

Reference Implementation and TestScripts:

  • Karell Ruiz, HealthLX
  • Joel Walker, HealthLX
  • Carie Hammond, Aegis

Special thanks go to the numerous individual who have participated on conference calls, ballots, and reviews of this IG:

  • Celine Lefebvre, AMA
  • Andrea Preisler, AHA
  • Isaac Vetter, Epic
  • Brett Stringham, Optum
  • Chris Johnson, Blue Cross and Blue Shield of Alabama
  • Diederik Muylwyk, Smile CDR
  • Nick Radov, Optum
  • Linda Michaelson, Optum
  • Peter Gunter, VA
  • Scott Fradkin, Flexion
  • Andrew Barbieri, Epic
  • Hans Buitendijk, Oracle
  • Kyle Johnsen, Epic
  • Liora Alschuler, Lantana
  • Mitra Rocca, FDA
  • Rob McClure, MD Partners, Inc.
  • Ron G. Parker, Canada Health Infoway
  • Spencer Utley, Epic