Mapping precoordinated LOINC terms to SNOMED concepts permits us to leverage the extensive SNOMED ontology of anaotomy, disease, pathology, morphology and measurements. (This also takes a major step towards normalizing clinical data for use in post-market surviellance.)

LOINC model

LOINC terms identify tests in terms of six axes (from LOINC, a Universal Standard for Identifying Laboratory Observations: A 5-Year Update):

Component (analyte): e.g., potassium, hemoglobin, hepatitis B antigen
Property measured: e.g., a mass concentration, enzyme activity (catalytic rate)
Timing: i.e., whether the observation applies to a moment in time or is an average or amount taken over a period of time, as is the case for a 24-h urine sodium concentration
System: i.e., type of sample or organ examined: e.g., urine, blood, chest
Scale: e.g., whether the measurement is quantitative (a true measurement), ordinal (a ranked set of options), nominal, or narrative (e.g., dictation results from x-rays)
Method used to produce the observation, but only when different methods give clinically significant different results

These are combined into a fully-qualifying string as like Rheumatoid factor:Titr:Pt:Ser:Qn (note that there is no method, implying that there is no clinical significance to different rheumatoid factor tests performed on blood serum). Expressed in RDF, a LOINC test could be defined in terms of SNOMED:

 loinc:Rheumatoid_factor:Titr:Pt:Synv_fld:Qn:LA 
     rdfs:subClassOf 
         [ owl:intersectionOf (
             # Rheumatoid factor
             snomedct:Rheumatoid_factor_measurement-procedure 
 
 	    # Titr
             [ owl:onProperty snomedct:method-attr ;
               owl:someValuesFrom snomedct:Titration_method-procedure ]
 
 	    # @@ Pt
 
 	    # Synv_fld
             [ owl:onProperty snomedct:Finding_site-attr ;
               owl:someValuesFrom snomedct:Synovial_cytologic_material-specimen ]
 
             # @@ Qn
 
 	    # LA
             [ owl:onProperty snomedct:method-attr ;
               owl:someValuesFrom snomedct:Latex_agglutination_test-procedure ]
         ) ] .

Issues

Has Apelon done this?
Are partial mappings sufficient for progress towards use cases?

For the Rheumatoid factor analyte, we have:

1 analyte:
- Rheumatoid factor bioportal, LOINC term - CUI:C0035448
2 properties:
- ACNc (Arbitrary Concentration) bioportal, LOINC term - CUI:C1264649
- Titr (Dilution Factor) bioportal, LOINC term - CUI:C0475208
1 timing:
- Pt (Point in time) bioportal, LOINC term - CUI:C1442880
4 systems:
- Body fld bioportal, LOINC term - CUI:C1829665
- Ser bioportal, LOINC term ?? - CUI:C0229671
- CSF bioportal, LOINC term - CUI:C0007806
- Synv fld bioportal, LOINC term ?? - CUI:C1550662
2 scales:
- Qn (quantitative) bioportal, LOINC term - CUI:C1442116
- Ord (Ordered categorical responses) bioportal, LOINC term - CUI:C1442114
6 methods:
- unspecified (considered clinically insignificant)
- Aggl (Agglutination) bioportal, LOINC term - CUI:C1441458
- Sheep cell aggl bioportal, LOINC term - CUI:C1441744
- LA (Latex agglutination) bioportal, LOINC term - CUI:C0023117
- EIA (Immunoassay) bioportal, LOINC term - CUI:C3172404
- Nephelometry bioportal, LOINC term - CUI:C0027692

Enumarated LOINC terms

for Rheumatoid factor:

Rheumatoid factor:Titr:Pt:Synv fld:Qn:Aggl bioportal, LOINC term, hipaaspace - cui:C0797118
Rheumatoid factor:ACnc:Pt:Body fld:Qn bioportal, LOINC term, hipaaspace - cui:C1114110
Rheumatoid factor:ACnc:Pt:Body fld:Ord:Sheep cell aggl bioportal, LOINC term, hipaaspace - cui:C0941828
Rheumatoid factor:Titr:Pt:Ser:Qn:LA bioportal, LOINC term, hipaaspace - cui:C0367453
Rheumatoid factor:Titr:Pt:Ser:Qn:Sheep cell aggl bioportal, LOINC term, hipaaspace - cui:C0367457
Rheumatoid factor:ACnc:Pt:Plr fld:Qn bioportal, LOINC term, hipaaspace - cui:C2598415
Rheumatoid factor:ACnc:Pt:Ser/Plas:Qn bioportal, LOINC term, hipaaspace - cui:C0551356
Rheumatoid factor:ACnc:Pt:Body fld:Qn:Sheep cell aggl bioportal, LOINC term, hipaaspace - cui:C3172174
Rheumatoid factor:ACnc:Pt:Synv fld:Qn:Nephelometry bioportal, LOINC term, hipaaspace
Rheumatoid factor:ACnc:Pt:Ser:Ord:LA bioportal, LOINC term, hipaaspace
Rheumatoid factor:ACnc:Pt:Body fld:Ord:LA bioportal, LOINC term, hipaaspace
Rheumatoid factor:ACnc:Pt:Ser:Qn:Nephelometry bioportal, LOINC term, hipaaspace
Rheumatoid factor:Titr:Pt:Ser:Qn bioportal, LOINC term, hipaaspace
Rheumatoid factor:ACnc:Pt:Ser:Ord:Sheep cell aggl bioportal, LOINC term, hipaaspace
Rheumatoid factor:ACnc:Pt:Ser:Qn:EIA bioportal, LOINC term, hipaaspace
Rheumatoid factor:ACnc:Pt:Synv fld:Qn bioportal, LOINC term, hipaaspace
Rheumatoid factor:ACnc:Pt:Body fld:Ord bioportal, LOINC term, hipaaspace
Rheumatoid factor:Titr:Pt:Ser:Qn:Nephelometry bioportal, LOINC term, hipaaspace
Rheumatoid factor:Titr:Pt:Body fld:Qn:Sheep cell aggl bioportal, LOINC term, hipaaspace
Rheumatoid factor:ACnc:Pt:Body fld:Qn:Nephelometry bioportal, LOINC term, hipaaspace
Rheumatoid factor:ACnc:Pt:Ser:Ord bioportal, LOINC term, hipaaspace
Rheumatoid factor:ACnc:Pt:Body fld:Qn:EIA bioportal, LOINC term, hipaaspace
Rheumatoid factor:ACnc:Pt:CSF:Qn bioportal, LOINC term, hipaaspace
Rheumatoid factor:Titr:Pt:Synv fld:Qn:LA bioportal, LOINC term, hipaaspace
Rheumatoid factor:ACnc:Pt:CSF:Ord bioportal, LOINC term, hipaaspace
Rheumatoid factor:ACnc:Pt:Synv fld:Ord:LA bioportal, LOINC term, hipaaspace
Rheumatoid factor:Titr:Pt:Synv fld:Qn:Sheep cell aggl bioportal, LOINC term, hipaaspace
Rheumatoid factor:Titr:Pt:Body fld:Qn bioportal, LOINC term, hipaaspace

breakdown

Factored into a disjunctive normal form, that breaks down as:

6 Rheumatoid factor:ACnc:Pt:Body fld|Ser:Ord|LA:|Sheep cell aggl

1 Rheumatoid factor:ACnc:Pt:CSF:Ord 1 Rheumatoid factor:ACnc:Pt:Synv fld:Ord:LA

4 Rheumatoid factor:ACnc|Titr:Pt:Body fld:Qn:|Sheep cell aggl

3 Rheumatoid factor:ACnc:Pt:Body fld|Ser|Synv fld:Qn:Nephelometry 1 Rheumatoid factor:Titr:Pt:Ser:Qn:Nephelometry

2 Rheumatoid factor:ACnc:Pt:Body fld|Ser:Qn:EIA

1 Rheumatoid factor:Titr:Pt:Ser:Qn 1 Rheumatoid factor:Titr:Pt:Synv fld:Qn:Aggl