2025-02-05 - Laboratory Terminology Standards WG Meeting

Review actions log and issues and decisions log

KN / Feikje Hielkema-Raadsveld

Dutch software vendor whose software connects to that of Abbott. They are receiving SNOMED codes from the UK extension

• "code" : "1464671000000104",
• "display" : "Mean substance concentration of glucose in capillary blood using minimally-invasive continuous glucose monitoring device (observable entity))"
• "code" : "1464761000000101",
• "display" : "Coefficient of variation of mean substance concentration of glucose in capillary blood using minimally-invasive continuous glucose monitoring device (observable entity) "
• "code" : "1464781000000105",
• "display" : "Percentage of time in target glucose range to total glucose monitoring time using minimally-invasive continuous glucose monitoring device (observable entity) "
• "code" : "1464931000000109",
• "display" : "Mean number of self-monitored capillary blood glucose measurements per day (observable entity)"
• "code" : "1464911000000101",
• “display" : "Number of clinically significant hypoglycaemic episodes recorded by continuous glucose monitoring device (observable entity)"
• "code" : "1464941000000100",
• "display" : "Percentage of successful data capture time to total expected continuous glucose monitoring sensor wear time using minimally-invasive continuous glucose monitoring device (observable entity)"
• "code" : "1464891000000104",
• "display" : "Glucose Management Indicator expressed as substance concentration ratio (observable entity))"
• "code" : "1464891000000104",
• "display" : "Glucose Management Indicator expressed as substance concentration ratio (observable entity))"
• “code" : "1464831000000100",
• "display" : "Percentage of time below level 1 hypoglycaemic threshold to total continuous glucose monitoring time using minimally-invasive continuous glucose monitoring device (observable entity)"
• "code" : "1464821000000102",
• "display" : "Percentage of time below level 2 hypoglycaemic threshold to total continuous glucose monitoring time using minimally-invasive continuous glucose monitoring device (observable entity)"
• "code" : "1464801000000106",
• "display" : "Percentage of time above level 1 hyperglycaemic threshold to total continuous glucose monitoring time using minimally-invasive continuous glucose monitoring device (observable entity) "
• "code" : "1464791000000107",
• "display" : "Percentage of time above level 2 hyperglycaemic threshold to total continuous glucose monitoring time using minimally-invasive continuous glucose monitoring device (observable entity)"

Stan and Pam to take to LOINC-SI group to discuss options to make the codes available internationally 

Andrew to update on whether measurement is in capillary / whole blood vs adjusted for plasma

Qualitative and semi-quantitative representation in SNOMED CT

Carried over to next session

April 2025 business meeting session for this group

Face-to-face session would be beneficial to tackle some primary issues

Meeting slot has been allocated for Tuesday 8th April 9-12.30 CET

Jim Campbell to chair

Karim to co-chair

UK need to consider whether inheres_in is superfluous in lab result reporting and align with international terminology

On hold

Time aspect modelling

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

Internal UK NRC log for discussion

Daniel to give a short presentation on time aspect - needs further discussion

On hold

Discussed with lab experts and the requirement is the same as the LOINC Ontology - time-specific concepts must not be subsumed by unmodelled soft default implicit 'single point in time' concepts

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

Relative concentration of a substance in two different specimens

Relative concentration two different measurement properties

Young Bae recommended we look at IUPAC relative properties and ratios

What is the advantage in developing the full mathematical model in SNOMED CT? Limitations to what can be achieved

General consensus that we should pursue via MAG

Stan to feed back from LOINC-SI group - won't be in the 1st LOINC Ontology release

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

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

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 

Flagged for further discussion

What about the requirement to classify extensions?

Document the LOINC and NPU differentiation

Propose short presentation in Oslo

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