Bruce Goldberg

• Current content for (in vitro) allergy testing in SNOMED CT is not up to date and very limited in content.
• Proposal is to create a SNOMED observables extension for in vitro IgE allergy testing using existing LOINC content
• This will require creation of a proposed project plan with some specifics to move it on.
• Depending on the amount of work, it may need to be reviewed and approved by the SMT in order to allocate any resources to the work.
• Notes:
  • Currently IgE related allergy tests are located in the procedure hierrchy under 104381000 |Allergen specific immunoglobulin E antibody measurement (procedure)| (503 descendants)
  • It has been suggested that to accomodate certain member country use cases, this content would be retained in the SNOMED core to represent orderables while the observables would represent the corresponding observations. This would seem to require additional procedure content be added to the SNOMED core or that the cuurent SNOMED procedure content be added to the extension.
  • Some allergy content content modeled as observables in the LOINC ontology Allergy preview (904 concepts representing for the most part specific IgE against whole allergen extracts expressed as arbitrary concentration and as classes, the latter having 726748001 |Radioallergosorbent testing technique (qualifier value)| as a technique
• Proposal
  • Extension will be confined to specific IgE measurements
  • Decision needed regarding SNOMED extension with respect to specific IgE testing procedures vs. observables
  • Additional content needs to be decided upon:
    • Are classes necessay?
    • Review of exisiting content in terms of which important allergens may be missing in the LOINC ontology Allergy preview and which should perhaps be removed.
      • It is suggested that only tests common to the major test vendors and not produced by laboratories performing the tests be part of the extension
      • Allergen components (important ones to be decided upon by the Allergy CRG and perhaps by querying CMAG members) are currently not part of the LOINC ontology Allergy preview and need to be. Only 445354008 |Measurement of Ara h 2 immunoglobulin E (procedure)| is present in SNOMED CT.
      • Should we add allergen mixes and if so which?
      • Should we add LOINC content for specific activity (specific/total IgE) to the SNOMED extension?

• 769247005 |Abnormal immune process (qualifier value)| and 472963003 |Hypersensitivity process (qualifier value)| are often found together describing the Pathological process for many concepts.  Is there a standard for which attribute-value pair is included in a role group?  I've attached the stated view of 402312004 |Acute guttate psoriasis (disorder)| as an example.  
• Currently there is an extra relationship of "Pathological process = Hypersensitivity process" added to all the Grave disease concepts (and MG concepts) because an ancestor 427439005 |Immune hypersensitivity disorder by mechanism (disorder)| has this relationship. Is having that relationship outside of a group appropriate? Could the modeling be improved?
• Proposal for approval:
  • Create Immune hyperensitivity proceess (qualifier value) as a parent of 472964009 |Allergic process (qualifier value)| and 263680009 |Autoimmune process (qualifier value)|
  • Use Immune hyperensitivity proceess (qualifier value) to fully define 427439005 |Immune hypersensitivity disorder by mechanism (disorder)| which should be renamed to just Immune hypersensitivity disorder (disorder)
  • Define subtypes of 427439005 |Immune hypersensitivity disorder by mechanism (disorder)| with newly created subtypes of Immune hyperensitivity proceess (qualifier value e.g. Type 1, Type II, Type II, Type IV immune hypersensitivity process (qualifier values) 
  • Retire 609407009 |Immune hypersensitivity reaction by mechanism (disorder)|
• New nomeclature for Hypersensitivity disorders proposed by EAAACI
  • Definition of Hypersensitivity renains the same
  • Definition of Allergy changed to emphasize it is a response to an exogenous stimulus in order to differentiate from autoimmunity.
  • New subtypes of type IV hypersensitivity (IVa T1, IVb T2, IVc T3) proposed
  • Additional types of hypersensitivity suggested (type V, VI, VII)
• We should restrict our efforts at this time to Types I, II, III and IV pending widespread clinical adoption of Type IV subtypes and Types V, V1 and VII.