What Is The Difference Between XDS,XDS.a,XDS.b and XDS-I?

By on May 22, 2012

IHE (Integrating the Healthcare Enterprise) create a profile called XDS, which is a generic term to reference all XDS profiles.  XDS.a and XDS.b are implementation profiles that describe technically how the implementation will be done.  XDS-I is an XDS implementation specifically for medical imaging.


XDS now refers to both XDS.a and XDS.b ( a family of profiles )

XDS.a is what you thought of as XDS last year.

XDS.b is a new profile which introduces:

  1. Updated web services including the use of WS-Addressing
  2. Updated Registry standard (ebRIM and ebRS 3.0)
  3. Use of MTOM in the Provide and Register transaction (and in the new WS Retrieve transaction as well)
  4. WS Retrieve – a full web services document retrieve to replace HTTP GET which uses MTOM and is capable of retrieving multiple documents in a single request

With XDS.b you loose the following capabilities from XDS.a:

  1. SQL query (remember that SQL query is optional in XDS.a Registry implementations)
  2. Retrieve via HTTP Get
  3. Use of SOAP with Attachments
The illustration below shows data flow in a typical XDS environment.  When data is initially created, it is stored in its native repository (database).  Once the data is stored, the repository announces the existences of the document to the XDS Registry.  The repository sends the document metadata as well as information about where it is stored to  the Registry.
A consumer can then Query the XDS Registry to see if there are any documents regarding a patient.  If the Registry contains a document the Consumer wants, the document can be accessed directly from the Consumer’s workstation or application.  As you recall information about the document’s location was sent to the Registry.  The Registry doesn’t contain the document, however it does contain the document metadata as well as it’s storage location.


For more information please go to www.ihe.net

About dkorolyk

I've been involved in Healthcare IT and PACS since Y2k. Over the years I've been fortunate enough to be involved in a lot of interesting an diverse projects. My experience also includes numerous HL7/EMR integration projects as well as many hardware and software platforms. My three main areas of expertise include technical integration aspects of radiology, oncology and laboratory diagnostics.

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