The MAP_TO table is used to identify the appropriate replacement for LOINC terms that have been DEPRECATED or DISCOURAGED. You can find a detailed explanation in section 11.2 of the LOINC Users’ Guide.
I have examined the MAP_TO table distributed in the 2.59 release of LOINC. I can find no LOINC number in the MAP_TO.LOINC or MAP_TO.MAP_TO column that does not also appear in the LOINC.LOINC column. Can you please provide examples of the LOINC numbers that you cannot find?
Regards,
John