Evaluating diagnostic accuracies of Panbio™ COVID-19 rapid antigen test and RT-PCR for the detection of SARS-CoV-2 in Addis Ababa, Ethiopia using Bayesian Latent-Class Models (BLCM)

Background Rapid diagnostics are vital for curving the transmission and control of COVID-19 pandemic. Although many commercially available antigen-based rapid diagnostic tests (Ag-RDTs) for the detection of SARS-CoV-2 are recommended by the WHO, their diagnostic performance has not yet been assessed in Ethiopia. So far, the vast majority of studies assessing diagnostic accuracies of rapid antigen tests considered RT-PCR as a gold standard, which inevitably leads to bias when RT-PCR is not 100% sensitive and specific. Thus, this study aimed to evaluate the diagnostic performance of Panbio ™ COVID-19 rapid antigen test jointly together with the RT-PCR for the detection of SARS-CoV-2. Methods A prospective cross-sectional study was done from July to September 2021 in Addis Ababa, Ethiopia, during the third wave of the pandemic involving two health centers and two hospitals. Diagnostic sensitivity and specificity of Panbio™ rapid antigen test and RT-PCR were obtained using Bayesian Latent-Class Models (BLCM). Results 438 COVID-19 presumptive clients were enrolled, 239 (54.6%) were females, of whom 196 (44.7%) had a positive RT-PCR and 158 (36.1%) were Ag-RDT positive. The Ag-RDT and RT-PCR had a sensitivity (95% CrI) of 99.6 (98.4-100), 89.3 (83.2-97.6) and specificity (95% CrI) of 93.4 (82.3 - 100), 99.1 (97.5-100) respectively. Most of the study participants, 318 (72.6) exhibited COVID-19 symptoms and the most reported was cough 191 (43.6). Conclusion The diagnostic performance of Panbio™ COVID-19 Ag RDT is coherent with the WHO established criteria of having a sensitivity ≥80% for Ag-RDTs. Superior performance of the Panbio™ RDT was documented in samples with the lowest cycle-threshold RT-PCR values and clients with confirmed clinical symptoms. Thus, we recommend the use of the Panbio™ RDT for both symptomatic and asymptomatic individuals in clinical settings for screening purposes. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This work was financed by Addis Ababa University through adaptive research and problem solving project, with project title, Evaluation and Validation of the Diagnostic Performance of SARS-CoV-2 rapid test for the detection of Novel Corona Virus, Ref #-PR/5.15/590/12/20 and no external funding was received. The funders anywhere not involved in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The contents are purely the responsibilities of the authors and did not represent and reflect the view of the funder. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ethical approval was obtained from IRB of department of medical laboratory Sciences, College of Health Sciences, Addis Ababa University (reference-MLS/174/21)), IRB office of Health bureau, AAPHREML (Reference-AAHB/4039/227) and also from Addis Ababa University, College of natural and computational science IRB (IRB-CNCSDO/604/13/2021). Additionally, AAPHREML wrote support letter to the study health facilities. During data collection process the data collectors informed each study health facility and study participants about the purpose and anticipate benefits of the research and on their full right to refuse, withdraw or completely reject part or all of their part in the study. Written informed consent on the use of data with full anonymity was obtained from the voluntary participants. This work has been done and performed as per Helsinki declaration. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes All data set used in this study are included in this manuscript.