Publisert - 07.05.2026

Conversion Mapping

This document describes how upstream FHIR resources are mapped to output models by ConversionService.

PlanDefinition + ActivityDefinition → TreatmentGroup

Source	Output field	Logic
`PlanDefinition.Identifier[0].Value`	`id`	First identifier value
`PlanDefinition.Name`	`name`	Direct mapping
`PlanDefinition.Description`	`description`	Direct mapping
`PlanDefinition.Extension` or `PlanDefinition.Type`	`diseaseGroup`	First checks for an extension with URL containing "diseaseGroup" and uses its `ValueString` (other value types are ignored). Falls back to `Type.Text` or `Type.Coding[0].Display`
`PlanDefinition.UseContext[].ValueCodeableConcept.Coding[]`	`jurisdictions`	Filters for codings where `System` equals `urn:oid:2.16.578.1.12.4.1.102` (RHF OID)
`PlanDefinition.EffectivePeriod`	`validityPeriod`	Direct mapping (Period with `start` and `end` as YYYY-MM-DD strings)
`PlanDefinition.LastReviewDate`	`reviewDate`	Direct mapping (YYYY-MM-DD string)
`PlanDefinition.Goal[].Addresses[]`	`indications`	Flattened list of CodeableConcepts from all goals
`PlanDefinition.Action[]` + `ActivityDefinition` lookup	`treatmentAlternatives`	See below

Treatment Alternative Resolution

Each PlanDefinitionAction is resolved to a TreatmentAlternative:

DefinitionCanonical is used to look up the corresponding ActivityDefinition from a dictionary keyed by identifier value.
Lookup tries exact match first, then falls back to matching the last URL segment.
Rank is extracted from the action's extensions (URL containing "rank"). Falls back to the action's position index (1-based).

Source	Output field
Action extension with "rank" URL, or position index	`rank`
`ActivityDefinition.Identifier[0].Value`, or `DefinitionCanonical` as fallback	`treatmentId`
`ActivityDefinition.Name`, or `Action.Description` as fallback	`name`
`ActivityDefinition.Description`	`description`
`ActivityDefinition.ArticleNumbers`	`medicines`

Medicine References from ActivityDefinition

Each entry in ActivityDefinition.ArticleNumbers becomes a MedicinalReference. The reference and display fields are null for FEST-sourced medicines:

{
  "reference": null,
  "type": "FEST/LegemiddelPakning",
  "identifier": {
    "system": "FEST/Varenummer",
    "value": "<article number>"
  },
  "display": null
}

RegulatedAuthorization → ReimbursementGroup

Source	Output field	Logic
`RegulatedAuthorization.Identifier[0].Value`	`id`	First identifier value
`RegulatedAuthorization.Extension[]`	`legalBasis`	The first extension whose URL contains `reimbursementRegulation` (case-insensitive); its `ValueCodeableConcept` is used directly
`RegulatedAuthorization.Basis.Coding[]`	`indications`	Each coding in `Basis.Coding` becomes its own `CodeableConcept` (one indication per coding), preserving the diagnosis-per-entry model from upstream

Note: in upstream RegulatedAuthorization, Basis carries the diagnoses (e.g., ICD-10 codes) while the legal basis (e.g., H-resept §950) is delivered via the reimbursementRegulation extension — the mapping flips these into the consumer-friendly ReimbursementGroup shape.

Code Systems

OID / URI	Description	Used in
`urn:oid:2.16.578.1.12.4.1.102`	Norwegian Regional Health Authority (RHF)	Jurisdictions
`urn:oid:2.16.578.1.12.4.1.1.7110`	ICD-10 (Norwegian)	Indications, Reimbursement codes
`http://terminology.hl7.org/CodeSystem/meddra`	MedDRA	Indications, Reimbursement codes
`urn:oid:2.16.578.1.12.4.1.1.7427`	Reimbursement regulation codes	Reimbursement regulation
`FEST/Varenummer`	FEST article numbers	Medicine references

Extending the Mapping

The mapping logic lives in Api/Services/ConversionService.cs. Each field extraction is isolated in a private method (e.g., ExtractDiseaseGroup, ExtractJurisdictions). To adjust mapping for a specific field:

Identify the relevant Extract* or Build* method.
Modify the filtering or transformation logic.
The method is pure (no I/O), so changes can be verified with unit tests.

If the upstream FHIR API introduces new extension URLs, the conversion service will need to be updated to recognize them. Unrecognized extensions are currently silently ignored.

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