| 2 | Discussion around the attributes inheres_in and time_aspect |
| - Requirement for inheres_in:
- LOINC view is lab perspective so using direct_site and nothing is added to the logic by including inheres_in for blood science codes. The specimen SNOMED CT code models the substance so can be inferred if needed. The information is sufficient for the clinical side to know the specimen
- NPU view is the clinical perspective and so they require the inheres_in and will not need direct_site for machine-readable definition. Computational rules can be used to compute these equivalences with the LOINC Ontology as long as both sides apply the attributes consistently.
- Tech preview expression set models both inheres_in and direct_site
- UK extn models both inheres_in and direct_site - the initial model did not include inheres_in but it was subsequently added to align to tech preview expressions
2. Time_aspect - LOINC Ontology terminologists explained the inclusion of 'time_aspect - > single point in time' in the logical definition and 'at single point in time' for every reporting SNOMED CT concept version of a LOINC code that is otherwise a specified time point e.g. 24 hr Urine test
- If time_aspect is added only by exception for specific time points, as the UK has done, then the classification results are not representative of comparative lab test results - they need to classify as siblings. An unmodelled 'single point in time' test must not subsume a '24 hour urine test' as they are not the same in practice to be counted and compared as subtypes
| - UK need to consider whether inheres_in is superfluous and align with international terminology
- UK need to inform lab network that the subsumption relationships created by unmodelled 'single point in time' concepts are not accurately representative and ensure they agree to align to the international design and model all concepts
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