A false positive is a mistaken result of a scientific test. For example, if the result of a pregnancy test is a false positive, it indicates that a woman is pregnant when she is not.
...a high rate of false positive results.
false positive in British English
noun
1.
a result in a medical test that wrongly indicates the presence of the condition being tested for
2.
a person from whom such a result is obtained
Examples of 'false positive' in a sentence
false positive
About 9 per cent of people given body scans for cancerous tumours are at high risk of false positive results because their tummy fat confuses the scanner.
Times, Sunday Times (2006)
Up to 20 percent of subjects referred for complaints of chest pain may have just the opposite problem, a false positive test.