2025-05-14 - Laboratory Terminology Standards WG Meeting

Inheres_in (SORRY!)

 Should Inheres_in be to substance or body structure for anatomy. Genes are ging to be placed under body structure. Gunnar & Young Bae to check with Daniel

Follow up with EU group, Rob's group - how do we work to the same standard blueprint to design the structured model-terminology

grouping / panels

microbiology structured data

value sets

Documenting the decisions and outcomes of this group

Scott to check with Ian G which confluence location to begin developing guidance

Governance of terminology descriptions - preferred terminology e.g. substances (adrenaline vs epinephrine) - the challenge of standardising across European nations

UK NRC explained the authoring and governance process with users / user groups / professional bodies / secondary research

SI explained governance process 

International decision for sharing and reusing path and lab SNOMED CT observable entity content

These concepts are modelled with both inheres_in and direct_site

Farzaneh to take these back and discuss internally for a steer on the use of inheres_in for these concepts

On hold

SI propose to remove inheres_in but await formal decision from this group

colour, appearance, identification

Proposed to revisit after reviewing the resources

Concept is primitive if the description is more specific than the modelling. Concept logical definition must not be more specific than concept description

LOINC uses time_aspect NPU is implied

Definition - Time of specimen collection

Must be stated consistently  in description AND modelling in accordance with SI editorial policy

modelling single point in time explicitly to enable correct classification of content

Time-specific concepts must not be subsumed by unmodelled soft default implicit 'single point in time' concepts

UK NRC to discuss applying the same principle

Inheres_in effectively duplicates direct_site. They are two different perspectives (lab and clinical) of the same target

Direct_site is suitable for sample-based diagnostics and not other areas but NPU will not be following those guidlines

In Cancer Synoptic histology - carcinoma inheres_in neoplasm, when specimen is taken, the direct_site is specimen 

LOINC and NPU share linkage via 3 attributes, as SNOMED CT concepts they will classify as siblings, because of the different use of Inheres_in and direct_site

Can compute mapping using ECL

Some challenges e.g. NPU uses units, LOINC does not

Direct_site attribute sufficiently captures specimen and derivable substance / site from specimen modelling 

LOINC Ontology to model direct_site

NPU to model inheres_in

Create interoperable rules and document in guidance 

LOINC and NPU take different approached (to be documented)

UK NRC need to decide approach

Representation of percent

Concept is primitive if the description is more specific than the modelling. Concept logical definition must not be more specific than concept description

unit not required field in LOINC so in SNOMED CT, if fully defined without unit, could generate logical equivalences 

Represent percent in the description and the unit in SNOMED CT in accordance with SI editorial policy 

LOINC Committee decided to remove 100 denominator and reflect percent as UoM. LOINC Ontology will only release codes with 'fraction property (e.g number fraction, mass fraction)' and percent will be identified by unit.

Percent unit is used with NPU. NPU is more standardised with use of units so there is less variation (e.g. for substance conc, one unit)

International content will continue to model percent unit according to cancer synoptic content - any question mark for moving to LOINC Ontology?

UK will maintain SNOMED CT percentage subtypes to support the UK labs migration from Read, modelling percent unit as standardised exceptions, but align to LOINC Ontology properties in order to compute equivalences (when combined with unit %) and classify as subtypes if needed 

Inconsistencies - International content for cancer synoptic reporting by immunohistochemistry

1255078008 | Percent of cell nuclei positive for proliferation marker protein Ki-67 in primary malignant neoplasm by immunohistochemistry (observable entity) |

Does not use percent unit in modelling

e.g. 1 - modelling time_aspect -> single point in time but not stating this in the description

In contrast to LOINC Ontology examples that do state 'at single point in time' in the description and model in the logic

e.g.2 - use inheres_in whereas LOINC Ontology used direct_site

SI are adding percent unit to the content

Awaiting formal decision on inheres_in from this group

Awaiting formal decision on time_aspect from this group

How do we represent both axes of ordinal AND qualitative / semi-q in SNOMED CT model?

NPU descriptions in this link (not complete yet): https://labterminology.com/npu-concept-model/general-rules-on-result-type/...

Hierarchies are inconsistent for qualifiers that represent the targets of scale_type defining attribute for observable entity concepts (see presentation slides)

Both are ordinal scales 

Both represented as presence in LOINC and international SNOMED CT

Semi-q needs to be defined

UK need to make a distinction between qualitative and semi-q in the terminology

Relative concentration of a substance in two different specimens

Relative concentration two different measurement properties

CALCULATIONS

Young Bae recommended we look at IUPAC relative properties and ratios

Patient test results calculations - consistent approach to reference external formulae, and not represent in SNOMED CT observable entity concept model (including ratios)