Infectious Disease > > COVID-19– Persistent incorrect positives more typical in ladies, autoimmune conditions
by Katherine Kahn, Staff Writer, MedPage Today February 21, 2024
It was possible– albeit unusual– for individuals not contaminated with SARS-CoV-2 to have relentless incorrect favorable quick antigen COVID-19 tests, longitudinal information revealed.
Amongst a big associate of over 11,000 individuals, 1.7% had at least one false-positive COVID-19 fast antigen test regardless of concurrent unfavorable molecular tests, according to a quick report in the New England Journal of Medicine
The majority of those individuals had incidental incorrect favorable tests– suggesting they likewise had at least one unfavorable quick antigen test throughout the research study duration– however 13 individuals had relentless false-positive COVID-19 quick antigen tests without any unfavorable tests, Apurv Soni, MD, PhD, of the University of Massachusetts Chan Medical School in Worcester, and coworkers reported.
“It is essential to keep in mind that this is an incredibly unusual phenomenon– in our report about 2% of individuals evaluated [falsely] favorable,” Soni commented to MedPage Today in an e-mail. “That is a comparable false-positive rate reported for a lot of antigen tests.”
Incorrect unfavorable outcomes are understood to happen relatively often with quick antigen COVID-19 tests and, to a lower degree, with the more precise RT-PCR tests. Incorrect positives are believed to be much less typical.
Soni stated that incorrect favorable COVID-19 antigen test outcomes have actually not been formerly explained before as a possible methodical problem. “There have actually been erratic reports of lot-specific tests malfunctioning, however what we observed was independent of lots and test types,” she described.
Her group reported that particular groups might be more susceptible to getting these incorrect positives.
Twelve of the 13 individuals with consistent incorrect favorable tests were females and all however one had actually utilized the Quidel QuickVue test.
Significantly, 6 of the 13 individuals reported having an autoimmune condition versus 10 out of the 178 with tests that were by the way favorable (OR, 14.4, 95% CI 3.2-59.9). Of the 6 people with autoimmune conditions, 2 had rheumatoid arthritis, one had Sjögren’s syndrome, one had lupus and antisynthetase syndrome, and 2 had unknown autoimmune conditions.
One prospective description for the relentless false-positive tests amongst individuals with autoimmune illness is that rheumatoid aspect is understood to cross-react with test antibodies, the authors discussed. This cross-reactivity “might possibly happen in any client who has actually a condition identified by flowing rheumatoid aspect.”
“Now that we have this details, the doctors who take care of such clients– mainly rheumatologists– can notify their clients that if they believe they may have COVID, they will need to do the more conclusive PCR test, due to the fact that the at-home test is not going to be reputable” in clients with autoimmune illness, William Schaffner, MD, of Vanderbilt University Medical Center in Nashville, Tennessee, commented to MedPage Today
“Although these quick tests are hassle-free for the neighborhood,