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

Sleep apnoea is estimated to impact more than 1 billion people worldwide and, in most cases, goes undiagnosed. —Prakhar Khanna, Forbes.com, 22 May 2026

Up to 70% of affected people currently go undiagnosed. —Samantha Agate, Fort Worth Star-Telegram, 19 May 2026

However, Larson died the night of the final rehearsal and just one day before Rent's first Off-Broadway preview performance, at the age of 35, from an aortic dissection, believed to have been caused by undiagnosed Marfan syndrome. —Meredith Wilshere, PEOPLE, 17 May 2026

In court Friday, Kazarian said her client suffered from an undiagnosed neurological disorder and may have experienced a seizure at the time of the collision. —Clara Harter, Los Angeles Times, 9 May 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