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On-Demand Documents and Deferred Document Assembly

Karen Witting – IBM

Co-chair ITI Technical Committee

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On-Demand Documents Use CaseUseful for sources of healthcare data which prefer to find and assemble most up-to-date document content at the time of requests for contentFinding and assembling data upon retrieve request Documents On-DemandOn-Demand Supplement Supports: Registration of On-Demand Documents Single Consumer Query lists stable documents and on-

demand data sources Consumer Retrieve from on-demand data sources

causes document content to be dynamically identified and assembled

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XDS On-Demand Documents Actors/Transactions

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XDS Document Entry typesXDS Document Entry types defined Stable Document Entry – metadata about a specific

and static set of healthcare content formed into a document. The source registers a Stable Document Entry when a meaningful collection of data should be published based on clinical events.

On-Demand Document Entry – metadata describing the characteristics of a set of on-demand content and a unique identifier which can be used to create a document which collects the latest, most recent available information at the time of retrieval.

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XDS On-Demand Workflow

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XCA workflow (no XDS)

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Deferred Document Assembly Use Case

Allows some sources of healthcare data to operate in a more efficient way

Allows source systems to register the existence of stable document content but defer actually assembling the document content only if and when it is retrieved.

Preferred in an application architecture where a great deal of content is available for sharing but saved as a set of distinct elementary records in a clinical database and not as documents. To convert all this content to documents is considered a waste of resources for any document which is never requested. Thus, only content that is specifically requested is formed into a document.

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Deferred Document AssemblyDeferred Document Assembly - Small enhancement XDS Content for a document identified and internally labeled Register documents with special hash/size 0 indicating deferred assembly

• Size = 0 (zero)• hash = da39a3ee5e6b4b0d3255bfef95601890afd80709 (SHA1 hash of a zero length file)

At retrieve previously identified content is assembled into document and hash/size updated

Repeated retrieve requests always returns the exact same contentActors Integrated Document Source/Repository grouped with Document Administrator

declares Deferred Documents Option Document Registry with Document Metadata Option Document Consumer with Deferred Documents Option

Workflow Integrated Document Source/Repository registers Stable Entry with:

• Size = 0 (zero)• hash = da39a3ee5e6b4b0d3255bfef95601890afd80709 (SHA1 hash of a zero length file)

Document Consumer retrieves document causing Document Source/Repository to assemble content, update size/hash in Document Registry and return complete content

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XDS Deferred Workflow