NPCR-internal code system identifying the four component types that together represent a Gleason score assessment in NPCR Anmälan: primary Gleason grade, secondary Gleason grade, Gleason sum, and Gleason missing flag.

This CodeSystem is used as the code binding for Observation.component.code in five Gleason-related Profiles: NPCRGleasonScoreObservation (Summary), NPCRGleasonScoreTargetedBiopsyObservation, NPCRGleasonScoreSystematicBiopsyObservation, NPCRGleasonScoreUnclearBiopsyObservation, and NPCRGleasonScoreTURPCystoObservation. All five profiles share the same component structure, enabling FHIR component slicing discrimination across the four elements of a Gleason assessment.

Rationale: NPCR Informationsspecifikation §7 does not provide terminology bindings for Gleason score components (systematic documentation gap, same pattern as MR findings). International terminology systems such as LOINC do contain some Gleason-related codes (e.g., 84904-2 for Gleason score at positive margin, 94734-1 for ISUP prostate cancer grade group), but these address specific clinical scenarios and do not collectively represent the NPCR-required primary/secondary/sum/missing structure. This NPCR-internal CodeSystem preserves documentation fidelity by mirroring NPCR's Variabelbeskrivning variable structure.

Thesis Discussion note: Component slicing in FHIR requires a discriminating code value on each component; Observation.code can be left unbound because meta.profile serves as resource identification, but component.code cannot be left empty. This pragmatic necessity forces an NPCR-internal binding where NPCR documentation provides none — a documented tradeoff between documentation fidelity and FHIR structural constraints.