Diagnostic evaluation of PanBio, and standard Q COVID-19 rapid antigen tests for the detection of SARS-CoV-2: a cross-sectional study from Nepal

The diagnosis of COVID-19 infection was time-consuming and costly, contributing to rampant transmission, particularly in developing countries like Nepal. This study aimed to compare the diagnostic performance of two rapid antigen diagnostic tests (RDTs, PanBio and Standard Q) against real-time reverse transcriptase PCR (rRT-PCR). This retrospective cross-sectional study was conducted among 1171 suspected COVID-19 patients at a provincial hospital in Nepal. Each participant provided two nasopharyngeal swabs, one for RDT and the other for rRT-PCR, spanning a total duration of four months. Sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy of each RDT, as well as the combined antigen-RDT, were determined in reference to the rRT-PCR status. The sensitivity and specificity of PanBio were 60.87% (95% CI: 55.84–65.74) and 98.43% (95% CI: 96.80–99.37), respectively, while that of Standard Q was 59.83% (95% CI: 53.16–66.23) and 96.15% (95% CI: 90.44–98.94), respectively. Positive and negative predictive values of PanBio were 97.14 and 74.20%, respectively, and that of Standard Q were 97.16 and 52.08%. The positive likelihood ratio was higher for PanBio (38.87, 95% CI: 18.56–81.41) than for Standard Q (15.55, 95% CI: 5.92–40.90). Meanwhile, the negative likelihood ratio was more than 0.40 for both RDTs. The accuracy for PanBio, Standard Q, and combined RDTs were 80.91% (95% CI: 78.08–83.52), 71.17% (95% CI: 65.98–75.98), and 78.14% (95% CI: 75.66–80.48), respectively. RDTs exhibited unsatisfactory sensitivity and positive predictive value, rendering them ineffective as a screening tool. Nonetheless, they demonstrated excellent specificity and negative predictive value. Hence, a negative test result almost entirely excludes the possibility of infection.