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One remedy is to customize your ontology trees to include the new concepts that are missing from the i2b2 ontologies. See Ontologies 201 – Custom Metadata – Additions and Modifications.

If your new concepts are not proprietary, then we recommend that your institution contact the appropriate coding authority, and ask them to include your new concepts into the next release of their terminology.

What if my institution's EHR is missing concepts that are found in one of the ontology trees?

If your institution's patient data do not include concepts from one of the ontology trees, then queries made from that tree's concepts may come up with zero results.

Trees with zero matching patient records can be handled in these ways:

• The tree can be renamed in the metadata-configuration table (TABLE_ACCESS) to include a caveat, for instance "tree name (Unused)."
• The tree can be deactivated in the metadata-configuration table (TABLE_ACCESS).
• Do nothing. Since the patient count is displayed for each concept in the ontology tree, those concepts will have no count, and researchers will be unlikely to use those concepts in a query.

Never fear! No institution will be using all of the concepts in every ontology tree. It is normal to have concepts in the ontology tree that match none of your patient records.

To prevent your institution's researchers from inadvertently choosing an "unused" concept in their queries, we recommend adding patient counts to each concept in the ontology tree. You can learn about how to do this in Ontologies 102 – Patient Counts ("totalnum").

Suggested Next Steps

• Visit Appendix D – i2b2 Ontology Tables to learn more about the structure of the metadata.
• Visit Appendix E – Test Queries to learn how to run some "sanity check" queries on your new ONT and CRC databases.
• Visit Ontologies 102 – Patient Counts ("totalnum") to learn how to add patient counts to your ontology concepts in the user interface.

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