In today's interconnected digital ecosystem, the seamless exchange of information between diverse systems is more critical than ever. A fundamental obstacle to achieving true interoperability lies in how different systems represent context information about concepts. Some systems embed this context directly within the terminology, using codes with rich, nuanced meanings. Others represent context through their information models, structuring data to convey context via relationships and attributes. This disparity creates a landscape where data exchanged between systems may lose its intended meaning unless carefully transformed and interpreted.
This chapter focuses on the strategies and methodologies for implementing transformations between these heterogeneous models. We will delve into the technical challenges of mapping context from terminologies to information models and explore practical solutions to bridge these differences. By examining real-world scenarios and leveraging interoperability standards, we aim to equip you with the knowledge and tools necessary to ensure that context is preserved and accurately conveyed during data exchange. Understanding these transformation processes is essential for developers, architects, and stakeholders striving to enhance interoperability and achieve consistent, reliable communication across varied systems.
Example of a transformation from a "Situation with explicit context" concept to a FHIR FamilyMemberHistory Resource information model


In the context of this SNOMED implementation guide, we have chosen to use the FHIR context model as an example of an information model for several reasons. FHIR is a widely adopted standard in the healthcare industry for exchanging electronic health records and related data. Its modular and extensible design makes it an ideal candidate to demonstrate how context information can be represented outside terminologies like SNOMED CT.
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The following table maps SNOMED CT “Situations with Explicit Context” subhierarchies to relevant FHIR resources, showing how clinical context is represented across terminology and information models.
Where FHIR Resource is listed as N/A, there may be no direct mapping in the base FHIR specification.
Context properties such as subject and temporal frame help clarify how the SNOMED concept aligns with FHIR resource attributes like subject, status, or effective[x].
The table below maps specific types of Situations with Explicit contexts to specific FHIR resources and states the associated context properties
As seen in the previous table, depending on the type of context represented in the SWEC concept, it can be transformed into a Condition or Observation resource. Here, we provide some examples of values for different key elements.
160266009 |No family history of clinical finding (situation)|
(None / N/A)
Clinical finding
Known absent
Person in the family
All times of past
1260502004 |History of event in life of subject (situation)|
Condition
Event
Known present
Subject of record
In the past
373572006 |Clinical finding absent (situation)|
Observation
Clinical finding
Known absent
Subject of record
Current or specified time
History Events with finding context
Observation
Event
Known absent
Subject of record
Current or specified time
373573001 |Clinical finding present (situation)|
Condition
Clinical finding
Known present
Subject of record
Current
443859009 |Possible clinical finding (situation)|
Condition
Clinical finding
Known possible
Subject of record
Current or specified time
443938003 |Procedure carried out on subject (situation)|
Procedure
Procedure
Done
Subject of record
Current or specified time
416237000 |Procedure not done (situation)|
Procedure
Procedure
Not done
Subject of record
Current or specified time
439763000 |Procedure on family member (situation)|
Procedure
Procedure
—
Person in the family
Current or specified time
Associated finding
<< Clinical finding
Associated finding
<< Clinical finding
Finding context
Known absent
Procedure context
Done
Procedure.category
Surgical
(Ancestor)
Surgical procedure
Procedure.reasonCode
Disease
Has focus
<< Clinical finding
Procedure.bodySite
Body site
Procedure site - direct
<< Anatomical structure
417662000 |History of clinical finding in subject (situation)|
Condition
Clinical finding
Known present
Subject of record
In the past
416471007 |Family history of clinical finding (situation)|
FamilyMemberHistory
Clinical finding
Known present
Person in the family
Condition.clinicalStatus
inactive
Temporal context
In the past
Condition.code
Condition.clinicalStatus
active
Temporal context
Current
Condition.code
Observation.code
Clinical finding
Associated finding
<< Clinical finding
Observation.value
Procedure.code
Procedure
Associated procedure
<< Procedure
Procedure.status
Current or past
Clinical finding
Clinical finding
Known absent
Completed
Transforming information between the SNOMED concept model and a FHIR representation is a clear use case for interoperability or analytics. Creating a set of rules to reproducibly perform these transformations safely in real-world scenarios is possible.
We represent these rules as a decision table to offer a clear and structured approach to handling the heterogeneity between terminologies and information models. Although the list provided is not exhaustive and serves only as an example, it effectively demonstrates the critical considerations and steps involved in the transformation process. This approach helps readers understand not just the theoretical aspects but also the practical implementation of transformation rules, enabling them to apply similar strategies within their own systems to achieve seamless interoperability.
417662000 |History of clinical finding in subject (situation)|
Known present
Subject of record
In the past
Condition
clinicalStatus = inactive
416471007 |Family history of clinical finding (situation)|
Known present
Person in the family
Current or past
FamilyMemberHistory
To further illustrate the practical application of these transformation rules, we have developed a demonstration tool that performs real-time conversions from SNOMED CT to FHIR. This tool serves as a concrete example of how context information can be effectively translated between different models using a similar set of rules. It is open source, and the code is publicly available for anyone to review, use, or modify.
relationship = << 303071001 |Person in the family (person)|
1260502004 |History of event in life of subject (situation)|
Known present
Subject of record
In the past
Condition
clinicalStatus = inactive
373572006 |Clinical finding absent (situation)|
Known absent
Subject of record
Current or specified time
Observation
observation.code = associated finding observation.value = known absent
373573001 |Clinical finding present (situation)|
Known present
Subject of record
Current
Condition
verificationStatus = confirmed
443859009 |Possible clinical finding (situation)|
Known possible
Subject of record
Current or specified time
Condition
verificationStatus = unconfirmed
