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

People also must be tested for HIV prior to starting the drug and with each injection; drug-resistant HIV has been identified when used by people with an undiagnosed HIV infection. — ABC News, 2 Nov. 2026

Snoring can be a signal of undiagnosed sleep apnea, which carries cardiovascular risk. — Samantha Agate, Charlotte Observer, 24 Oct. 2026

Tuesday, the sheriff announced an autopsy found that Greer actually died from an undiagnosed medical condition. — J.d. Miles, CBS News, 20 Oct. 2026

New research suggests concussions can quietly shut down the brain’s control over testosterone, and the hormonal fallout often goes undiagnosed long after the headaches fade. — Samantha Agate, Miami Herald, 19 Oct. 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