There are some mapping errors in the concept_relationship table where some concept codes have incorrect mappings and some other concept codes are missing a mapping.
For example, the source_code “I50.40” with source_code_description “Unspecified combined systolic (congestive) and diastolic (congestive) heart failure” should not be mapped to standard concept 44782718 since there are only two concept codes “428.41” and “I50.41” under that concept (concept_code=“153931000119109”) on UMLS Terminology Services. So, the “map_to” relationship in the concept_relationship table for code “I50.40” with concept_id_1=45533457 and concept_id_2=44782718 seem to be incorrect.
Base on data on the UMLS Terminology Services, the source codes “I50.33” and “428.33” should be both mapped to the standard concept_id 40481043 (concept_code=“443844007”). I think there is a missing “map_to” relationship in the concept_relationship table for code “I50.33” with concept_id_1=45562355 and concept_id_2=40481043.