Lessons Learned - Mapping LOINC RadLex into EHR's that do not have LOINC fields

I am looking for some lessons learned on the approach used to map LOINC RadLex terms and codes into an EHR that does not have fields dedicated specifically for this information in the order build tools. This EHR solution has been in use for over 15 years and has many customized order names to address things like local operational workflows. The desire is to now align with the LOINC standards.