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

But some experts warn that mass testing of average-risk healthy people who are not showing symptoms could lead to false positive results, doing more harm than good. —Jacqueline Howard, CNN, 8 Apr. 2024

In the seven months that the Evolv scanners were active, 50,000 of the 194,000 scans resulted in a positive alarm — 85 percent of which were false positives. —Gaby Del Valle, The Verge, 2 Apr. 2024

There were also false positives, or cases when a person was mistakenly identified as being connected to Hamas, the officer said. —Sheera Frenkel, New York Times, 27 Mar. 2024

Cross-reactivity: Some tests may react with other substances in the body, like a similar virus or a non-specific protein, resulting in a false positive result. —Alyssa Hui, Verywell Health, 1 Mar. 2024

Those are the various false positives and false negatives that would be part of the risk model. —Lance Eliot, Forbes, 29 Feb. 2024

Even if someone didn’t recently have COVID, using a stool sample could still lead to false positive results, said William Schaffner, MD, professor of infectious diseases at the Vanderbilt University Medical Center. —Julia Landwehr, Health, 6 Feb. 2024

These detectors often yield false positives due to relying on unproven detection metrics. —Benj Edwards, Ars Technica, 8 Sep. 2023

There are government-run lists as well as private services used by banks for things like anti-money laundering or terrorist financing screenings, Martin says, but these are often incomplete or inaccurate, and false positives can occur in regions where people have similar names. —Mia Sato, The Verge, 29 Feb. 2024

Word History

First Known Use

1912, in the meaning defined above

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