Now that we’ve gone over the basics required for understanding the LOINC® Document Ontology in June’s tip of the month, let’s talk about how to search for LOINC® documents – which can be difficult. The Document Ontology has specific rules for what can or cannot be included within a document name or a document attribute. To recap, the five attributes that define a LOINC® document are:

• Type of Service (in the Component axis)
• Kind of Document (also in the Component axis)
• Setting (in the System axis)
• Subject Matter Domain (in the Method axis)
• Role (also in the Method axis)

When you look for documents that may already exist in the LOINC® Document Ontology, first search at a high level for the Component and Method in which the document is used. For example, you may be looking for an anesthesiology report or a mental health discharge summary. Anesthesiology and mental health would be Subject Matter Domains – thus search in the Method axis. An anesthesiology report would be a procedure note, found by searching for the Type of Service and Kind of Document within the Component axis – same for discharge summary.  See examples in the table below.

Curly braces – {  }  – in a LOINC® axis indicate that the LOINC® document does not specify the value; the document examples in the table above can all be used in multiple settings (Hospital, Outpatient Clinic, Emergency Department, etc.), which means that there is no need to search further for a more “specific” code once you have the Subject Matter Domain and Kind of Document you want.

Additionally, the LOINC® Document Ontology does not specify the following information in the document name or attribute values and is considered metadata:

• Document author name
• Location of service (e.g. Intensive Care Unit – Room 2)
• Date of service
• Document status (e.g. signed/unsigned)
• Security/privacy flags (e.g. protected)
• Amendments or updates

Lastly, one of the features LOINC® has included within the Document Ontology is groupings of like documents by similar components and methods under specific use cases. The LOINC® group LG90-3 (Document Ontology grouped by the Method and Component) is the parent of multiple document groups as seen in the figure below. LOINC® document groups allow for users to better build, display, and retrieve documents with similar attributes and is another way you can search “top down”, as shown below.LG90-3 Document Ontology grouped by Component.

 LG38811-2 (Procedure Note) – Any role or setting
       • LG38811-2 (Procedure Note) – Any role or setting
                      68630-3 Allergy and Immunology procedure note
                      84062-9 Anesthesiology procedure note
                      77422-4 Critical Care Medicine procedure note

      • LG38741-1 (Progress Note) – Any role or setting
                     78710-1 Cardiology progress note
                     78479-3 Neonatal Perinatal Medicine progress note

 LG92-9 Document Ontology grouped by Method
      • LG39269-2 (Women’s Health) – Any type of service, kind of document, or setting
                    85868-8 Women’s Health group counseling note
                    85856-3 Women’s Health risk assessment and screening note

For additional information, references to the terms used in the Document Ontology framework are located within the LOINC® class file DOC.Ontology . Users can also search for “LOINC Document Ontology” in RELMA to view details on the Document Ontology axes and their associated descriptions. If you have any questions regarding LOINC® Document Ontology or need help with terminology implementation or mapping, please contact us.