Death (cause unknown) (of) (unexplained) (unspecified cause)

Death (cause unknown) (of) (unexplained) (unspecified cause) is a main term in the FY2027 ICD-10-CM Alphabetic Index (Index to Diseases and Injuries). The Index lists R99 for the term on its own. It has 5 subterms and 5 code entries. First-level subterms include brain, cardiac, family member. Confirm any code you find here in the Tabular List before you report it.