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In the most basic sense, there are four possible outcomes for a COVID-19 test, whether it’s molecular PCR or rapid antigen: true positive, true negative, false positive, and false negative.
A false positive Covid-19 test result can happen, but it’s rare, says Brian Labus, Ph.D., M.P.H., assistant professor at the University of Nevada Las Vegas School of Public Health.
False positives "can happen with any test" and, if someone tests positive for COVID-19 with a rapid test but does not have symptoms, he recommends following up with a PCR test to confirm that this ...
Accuracy is measured in terms of specificity and selectivity. Test errors can be false positives (the test is positive, but the virus is not present) or false negatives, (the test is negative, but the virus is present). [179] In a study of over 900,000 rapid antigen tests, false positives were found to occur at a rate of 0.05% or 1 in 2000. [180]
Second, the person with a positive Antigen-RDT could be asymptomatic but a "contact of a probable or confirmed case." [10] Nevertheless, individual countries may have different case definitions of COVID-19; for example, in New Zealand a positive PCR test (not just a RAT) is necessary for a person to be considered a "confirmed case." [11]
The term has been adopted by alternative medicine advocate Joseph Mercola, who has exaggerated the effect of false positives in polymerase chain reaction (PCR) tests to construct a false narrative that testing is invalid because it is not perfectly accurate (see also § PCR testing, above). In reality, the problems with PCR testing are well ...
It’s possible for an expired COVID test to show a false positive—but it’s also possible for a non-expired COVID test to show a false positive, Dr. Russo says. It’s just not super likely ...
The false positive rate (FPR) is the proportion of all negatives that still yield positive test outcomes, i.e., the conditional probability of a positive test result given an event that was not present. The false positive rate is equal to the significance level. The specificity of the test is equal to 1 minus the false positive rate.