Col.Description
PLUILexical Unique Identifier in the previous Metathesaurus but not present in this Metathesaurus
LUILexical Unique Identifier into which it was merged in this Metathesaurus

From: 3, Metathesaurus - Rich Release Format (RRF)

Cover of UMLS® Reference Manual
UMLS® Reference Manual [Internet].
Bethesda (MD): National Library of Medicine (US); 2009 Sep-.

NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.