undiagnosed

adjective

un·​di·​ag·​nosed ˌən-ˌdī-ig-ˈnōst 

-əg-, 

-zd

: not diagnosed : not identified through diagnosis

an undiagnosed illness

… the symptoms of the syndrome may be subtle and thus may remain undiagnosed.

—Dwight R. Robinson

a condition that often goes undiagnosed

Examples of undiagnosed in a Sentence

Recent Examples on the Web

In February 2023, news broke that Jansen had died suddenly at age 28 from an undiagnosed heart condition. — Brianna Zigler, Entertainment Weekly, 17 Aug. 2026

In 2023, after the death of her brother Jansen, who died in 2023 from aortic valve complications and an undiagnosed large heart, Panettiere began spiraling with depression again. — Gillian Telling, PEOPLE, 17 Aug. 2026

The initial symptoms can be vague and, given its rarity, the infection is notorious for being undiagnosed or misdiagnosed. — Beth Mole, ArsTechnica, 12 Aug. 2026

In a confessional, the reality TV star says having an undiagnosed chronic condition has taken a mental toll on her. — Anthony Robledo, USA Today, 4 Aug. 2026

Word History

First Known Use

1864, in the meaning defined above

Medical Definition

undiagnosed

adjective

un·​di·​ag·​nosed -ˈnōst 

: not diagnosed : eluding diagnosis

undiagnosed disease