HealthDay News – The Abbott BinaxNOW COVID-19 Ag Card (BinaxNOW) rapid antigen test has lower sensitivity than reverse transcription-polymerase chain reaction (RT-PCR) for detecting severe acute respiratory syndrome coronavirus 2 infection, according to research published in the January 19 early-release issue of the US Centers for Disease Control and Prevention Morbidity and Mortality Weekly Report.
Jessica L. Prince-Guerra, PhD, from the CDC COVID-19 Response Team, and colleagues examined the performance of the BinaxNOW rapid antigen test. BinaxNOW was used with real-time RT-PCR testing for the analysis of 3419 paired specimens collected from persons aged 10 years and older during November 3 to 17, 2020, in Pima County, Arizona. Viral culture was performed on 274 of 303 residual real-time RT-PCR specimens positive by either test.
The researchers found that the BinaxNOW antigen test had a sensitivity of 64.2 and 35.8% for specimens from symptomatic and asymptomatic persons, respectively, with near 100% specificity in specimens from both groups. Virus was cultured from 35% of the specimens, including 57.8% of 147 specimens with concordant antigen and real-time RT-PCR positive results and 8.9% of 124 and none of 3 with false-negative and false-positive antigen test results, respectively.
“Despite their reduced sensitivity to detect infection compared with real-time RT-PCR, antigen tests might be particularly useful when real-time RT-PCR tests are not readily available or have prolonged turnaround times,” the authors write.