Anna made a relevant point in another thread.
She said:
Apart from that, there is a problem with SNOMED and LOINC being two standard vocabs for measurements with no connections between them. Improve LOINC representation in OMOP Vocabulary (Athena) (link parts to lab tests) - #6 by aostropolets
her diagram
It is an interesting problem of two SDOs: SNOMED International and Regenstrief. It would be good to consult an expert who knows the current status of the collaboration. See SNOMED International – LOINC (what is new in 2018 and 2019).