# | Ontology | Use in DDO | Classes | Object properties | Data properties | Total |
---|---|---|---|---|---|---|
Imported ontologies as whole | ||||||
 1 | BFO (Basic Formal Ontology) | Top-level reference ontology | 35 | 0 | 0 | 35 |
 2 | OGMS (Ontology for General Medical Science) | Mid-level reference ontology | 120 | 0 | 0 | 120 |
Imported from other external ontologies | ||||||
 1 | DOID (Human Disease Ontology) | Externally referenced disease classes | 1760 | 0 | 0 | 1760 |
 2 | SYMP (Symptoms Ontology) | Select classes for symptoms | 80 | 0 | 0 | 80 |
 4 | UO (Units of Measurement Ontology) | Laboratory tests units of measurements | 37 | 1 | 0 | 38 |
 5 | OBO RO (Relation ontology) | Object properties design | 0 | 19 | 0 | 19 |
 6 | RxNorm ontology | Externally referenced drugs and chemical substances | 1042 drug + 1069 substance | 0 | 0 | 2111 |
Imported from other external terminologies | ||||||
 1 | SNOMED CT | Select classes to enhance granularity of diseases, drugs, substances, symptoms, etc. | 1987 diseases, 72 symptoms, 83 laboratory tests, 1 disease course, 23 physical examinations, 5 diagnoses, 107 disorders, 23 living organisms (classes) | 2301 | ||
 2 | UMLS | Selection of concepts UMLS CUIs for all concepts | ||||
Total | 6444 | 20 | 0 | 6464 |