Diagnostic Accuracy of Antigen-Based Rapid Test during the Fourth Wave of COVID-19 in Edo State, Nigeria

Abstract

Background: Since the use of rapid test kits for diagnosis of COVID-19, diagnostic accuracy has been of concern, particularly in resource- limited settings. This study assessed diagnostic accuracy of Abbot Panbio antigen-based rapid diagnostic test (RDT) for COVID-19 using  polymerase chain reaction (PCR) as the gold standard in Edo State, Nigeria.

Methodology: We conducted a descriptive cross-sectional study during the 4th wave of the pandemic in Edo State from January 5 –  February 4th, 2022. Nasopharyngeal and oropharyngeal swabs were collected from 240 consenting participants at 10 sample collection  sites. The index test (RDT) and gold standard test (real-time reverse transcription PCR) were performed simultaneously. Sensitivity,  specificity, predictive values, and ROC analysis were conducted on the RDT compared to RT-PCR using SPSS version 26.0 software.  

Results: Thirty-six (15.0%) participants tested positive on RDT and 34 (14.2%) tested positive on PCR. RDT had a sensitivity of 73.5% (95%  CI: 66.0–81.0) and specificity of 94.7% (95% CI: 91.6-97.8) with a positive predictive value of 69.4% (95% CI: 55.8-80.7), and negative  predictive value of 95.6% (95% CI: 91.8-98.0). The area under the curve (AUC) of the ROC for the RDT against PCR was 84.1% (75.1% -  93.1%).

Conclusion: The diagnostic accuracy of the Panbio rapid antigen test for SARSCoV-2 was below WHO standards. However, they  remain useful tools for continued surveillance of the disease. Rigorous evaluations combining the results of rapid antigen tests with other  clinical information would prove useful for prompt diagnosis and surveillance of COVID-19 in Nigeria.