2025-04-02 - Laboratory Terminology Standards WG Meeting

1

Agenda for April face-to-face session

All

1. Welcome and introductions - KN or JC to introduce the group and our objectives

1. Time aspect - interpretations of using time_aspect attribute

2. Inheres_in and direct_site

   • NPU-SNOMED collaboration - Daniel (and colleagues) update

   • Farzaneh and Suzanne -  "Use of inheres_in for colour, appearance, identification".

3. Qualitative and semi-quantitative result observables - look at some common examples

4. Relative concentration model - follow up with Farzaneh and Suzanne

5. Document design and implementation guidance for lab observables ontology - Principles that apply to the lab domain

   1. relationships between the terminologies for labs, system implementations and terminology developers

   2. Strategy for how to reuse and share content

   3. Jim Campbell, Karim and Stan (I think!) volunteered to lead and write and SI can offer support

   4. references to respective editorial principles docs

Karim to chase LOINC Ontology reps for March release update

Reorder and prioritise agenda items 

 2

UK concept promotion request from Netherlands

AP / KN / Feikje Hielkema-Raadsveld

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

Blood glucose self-monitoring concepts

•  

  • "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

• Jim Case - still being discussed internally

• Jim Campbell -they're not about the results of a glucose measurement, which was what an observable is....they're about the procedure that is being used to measure the glucose.

Andrew update from SME - measurment is taken from interstitial fluid and calculated for plasma

Discussion around requirement for modelling 'calibrated / adjusted  for' test results e.g. done in blood but calibrated for plasma, interstitial fluid etc.

Description - .".. in interstitial fluid adjusted / calibrated for plasma"

modeling:

direct_site and the specimen (interstitial fluid)

inheres_in plasma

3

4

 AOB

1

April 2025 business meeting session for this group

KN / JC

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

2

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

KN / AP

We agree it does not add anything but need to add to internal UK NRC log for discussion

On hold

3

Time aspect modelling

KN / AP

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

4

SARS-Cov2 observable entity concepts for reporting viral RNA presence in the SNOMED CT International Edition

FA

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

5

Use of inheres_in for 

colour, appearance, identification

FA

inheres_in  used for the property to describe the characteristic of an organism, cell or body structure - applicable to LOINC Ontology representations

Farzaneh to present

6

Fractions and ratios

All 

IFCC-IUPAC Silverbook https://iupac.org/what-we-do/books/silverbook/ but also on the homepage: https://labterminology.com/list-of-kinds-of-property/

Proposed to revisit after reviewing the resources

7

Relative concentration of a substance in two different specimens

Relative concentration two different measurement properties

KN / DK

How do we assess effort vs impact? The requirement to model them accurately for machine reasoning - auto-classifications; erroneous subsumptions

Karim reviewed the modelling options with Daniel and presented to group

Relative_conc_modelling options.pptx

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

8

1

Time aspect specification in description AND modelling

All

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

2

Inheres_in is superfluous in lab result reporting

All

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

3

Representation of percent

All

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 

4

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) |

All

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

5

Qualitative and semi-quantitative representation in SNOMED CT

KN

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