false positive

noun

plural false positives

: a person or test result that is incorrectly classified as positive (as for the presence of a health condition) because of imperfect testing methods or procedures

A false positive—a test result indicative of disease that isn't actually present—can trigger a chain reaction of worry, further tests, and even unnecessary treatment.

—Harvard Health Letter

The quarantine could be lifted early if the lab confirms that the case was a false positive.

—Kathleen Moore

Perhaps more important, polygraph tests are notoriously unreliable. Scientists are understandably concerned about false positive results …

—Chemical & Engineering News

—often hyphenated when used before another noun

The technology could improve a radiologist's ability to detect breast cancers and it could lower the number of false-positive results …

—Laurie Tarken

compare false negative

Examples of false positive in a Sentence

Recent Examples on the Web

While the sample was a false positive, the FDA’s traceback investigation still converges on Taylor Farms lettuce as a suspect, and people should continue to obey the company’s voluntary recall, the FDA confirmed on X, formerly known as Twitter. — Janelle Mella, Charlotte Observer, 21 July 2026

There has been little progress in finding the outbreak’s source, despite the false positive test of Taylor Farms’ lettuce, after investigators believed it was linked to produce supplied to Taco Bell in five states. — Ty Roush, Forbes.com, 21 July 2026

Officials would not go into detail on what caused the faulty result, but contamination is a common source of false positives. — Beth Mole, ArsTechnica, 21 July 2026

Justin Sullivan | Getty Images The Food and Drug Administration stood by its main conclusions about the origin of the cyclosporiasis outbreak yesterday after its announcement of a false positive test led to confusion. — Alex Harring, CNBC, 21 July 2026

Word History

First Known Use

1912, in the meaning defined above

Rhymes for false positive

• seropositive
• causative
• dispositive
• electropositive

Medical Definition

false positive

noun

: a person or test result that is incorrectly classified as positive (as for the presence of a health condition) because of imperfect testing methods or procedures

Another problem with the test … is that it also produces a number of false positives; that is, a number of neonates with elevated trypsin levels the first time they are tested are found not to have elevated levels on the second test.

—The Journal of the American Medical Association

The urine dipstick test for protein can give false positive results when various pharmacologic agents and gross hematuria are present or when urine pH is high …

—Biff F. Palmer, Scientific American Medicine

—often hyphenated when used before another noun

… false-positive results that led healthy women to have unnecessary surgery.

—Denise Grady, The New York Times

The test can give false-positive readings, however, and it triggers a follow-up colonoscopy in 4% to 10% of cases.

—Marilyn Chase, The Wall Street Journal

compare false negative