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

Warren’s letter also questioned confusion about the FDA reporting that Taylor Farms’ lettuce had tested positive for Cyclospora, only to retract the claim the next day, calling it a false positive. — Beth Mole, ArsTechnica, 14 Aug. 2026

In February, a police officer pulled over a Chevrolet Tahoe based on a false positive by a Flock Safety license plate reader that reported the plate stolen. — Daniel McFadin, Arkansas Online, 13 Aug. 2026

Meanwhile, OpenAI has reportedly had the capacity to watermark ChatGPT text for years, but has not done so — reporting from the Wall Street Journal attributed that to concerns including false positives and competitive risk. — Anisha Sircar, Forbes.com, 13 Aug. 2026

Confusion was sparked last month when the Food and Drug Administration announced that a sample of lettuce from Taylor Farms that had tested positive for cyclospora was a false positive. — CBS News, 6 Aug. 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