Exploring UMLS MRHIER for Hierarchical Queries.

by Nadeem Nazeer

MRHIER file from UMLS contains one row for each hierarchy or context in which each atom appears. If a source vocabulary does not contain hierarchies, its atoms will have no rows in this file. If a source vocabulary is multi-hierarchical (allows the same atom to appear in more than one hierarchy), some of its atoms will have more than one row in this file.

MRHIER provides a complete and compact representation of all hierarchies present in all Metathesaurus source vocabularies. Hierarchical displays can be computed by combining data in this file with data in MRCONSO. The distance-1 relationships, i.e., immediate parent, immediate child, and sibling relationships, represented in MRHIER also appear in MRREL.RRF.

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  1. To find an atom’s siblings in a specific context, find all MRHIER rows by¬†CUI or AUI, and PTR values will provide its ancestor trees.
  2. To find an atom’s children in a specific context, append a period (.) and the atom’s AUI to its PTR and find all MRHIER rows and the expanded PTR values(recursively) will provide its sibling trees.

In coming blogs, we will discover how to dig deep for more specific hierarchical queries. You can check out my blogs on UMLS HERE!

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