Norwegian Laboratory Codebook (NLK) - FHIR Implementation Guide - Downloaded Version 0.2.2 See the Directory of published versions

Architecture

Technical Architecture

This page provides a detailed technical view of the Norwegian Laboratory Codebook (NLK) CodeSystem architecture and its integration within the FHIR ecosystem.

Complete System Architecture

The following comprehensive diagram shows the full technical architecture of the NLK CodeSystem, including all FHIR base classes, Norwegian-specific extensions, medical domain classifications, and integration patterns:

Figure: Complete technical architecture of the Norwegian Laboratory Codebook CodeSystem showing FHIR R4 foundation, domain-specific implementations, and Norwegian healthcare integration patterns.

Architecture Components

FHIR R4 Foundation

The NLK CodeSystem is built upon standard FHIR R4 base classes:

• CodeSystem: Core FHIR resource providing the foundation
• Property: Metadata definitions for concept properties
• Concept: Individual code entries with associated metadata
• ConceptProperty: Property values attached to specific concepts

Norwegian Laboratory Implementation

The Norwegian-specific implementation extends FHIR with:

• NorskLaboratoriekodeverk: Main CodeSystem implementation (11,391 codes)
• NLKProperty: Extended properties for Norwegian laboratory context
• NLKConcept: Laboratory code concepts with Norwegian healthcare metadata

Medical Domain Classification

Six major medical specialties organize the laboratory codes:

1. Medisinsk Biokjemi (Medical Biochemistry) - 2,881 codes
2. Immunologi og Transfusjonsmedisin (Immunology & Transfusion Medicine) - 3,231 codes
3. Medisinsk Mikrobiologi (Medical Microbiology) - 2,547 codes
4. Klinisk Farmakologi (Clinical Pharmacology) - 2,642 codes
5. Medisinsk Genetikk (Medical Genetics) - 67 codes
6. Patologi (Pathology) - 27 codes

FHIR Integration Patterns

The CodeSystem integrates with FHIR workflows through:

• ObservationProfile: Laboratory test results using NLK codes
• DiagnosticReportProfile: Comprehensive laboratory reports
• ValueSet: Curated subsets for specific use cases

Norwegian Healthcare Context

Integration with Norwegian health ecosystem:

• HL7 Norway Foundation: Built on hl7.fhir.no.basis package (v2.0.17)
• National Standards: Alignment with Norwegian healthcare interoperability requirements
• Jurisdictional Compliance: Norway-specific governance and terminology management

Implementation Benefits

This architecture provides:

• Standardization: Consistent laboratory terminology across Norwegian healthcare
• Interoperability: FHIR-compliant integration with existing systems
• Extensibility: Framework for future laboratory code additions
• Governance: Clear ownership and maintenance patterns
• Quality: Validated, deduplicated, and version-controlled terminology

Technical Specifications

• FHIR Version: R4 (4.0.1)
• CodeSystem URL: http://hl7.no/fhir/ig/nlk-test/CodeSystem/norsk-laboratoriekodeverk
• Version: 7280.77
• Status: Experimental
• Case Sensitive: True
• Content: Complete (all codes included)

For implementation guidance and examples, see the Getting Started section.