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

The new findings ruled that his death was accidental and probably stemmed from an undiagnosed condition — but noted that Naroditsky had ingested both methamphetamine and kratom, and that likely was a contributing factor. —Grace Toohey, Los Angeles Times, 22 Jan. 2026

Maybe this reveals some sort of hitherto undiagnosed neurodivergence, but asymmetric designs like this annoy me. —Nick Miller, New York Times, 21 Jan. 2026

The peak of a psychedelic experience can therefore share similarities with psychosis; and, for people with undiagnosed underlying conditions, this can increase the severity of manic and psychotic symptoms, as the findings of a recent paper concluded. —Mattha Busby, Rolling Stone, 16 Jan. 2026

Advocates report that girls with undiagnosed disabilities may struggle academically, repeat grades or disengage from education altogether. —Keely Cat-Wells, Forbes.com, 16 Jan. 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