[Evaluation of two COVID-19 antigenic diagnostic tests: and compared to ].

Introduction: the COVID-19 pandemic causes biological diagnostic problems that remain relevant in low-income countries in general and in Cameroon in particular. Rapids tests that reliably detect SARS-CoV-2 virus antigen present themselves as an important alternative in several contexts. The objective of our study was to evaluate the diagnostic performance of two rapid diagnostic tests BIOSYNEX COVID-19 Ag BSS and BIOSYNEX COVID-19 Ag + BSS, compared to each other and to the AmpliQuick SARS-CoV-2 PCR test.

Methods: a cross-sectional and comparative study was carried out from April 27 to May 29, 2021 in the city of Douala in Cameroon. The samples consisted of nasopharyngeal swabs received at the molecular biology laboratory of the Douala Gyneco-obstetric and pediatric hospital, whatever their origin. The socio-demographic parameters (age, profession, football players, travelers, others), marital status, nationality), comorbidity and known status of COVID-19, were recorded on the collection sites. The main collection sites were the Deïdo Health District and the Douala Gyneco-Obstetric and Pediatric Hospital. We performed the diagnosis of COVID-19 using the rapid diagnostic test (RDT) BIOSYNEX COVID-19 Ag BSS and RDT BIOSYNEX COVID-19 Ag + BSS compared to each other and to the AmpliQuick SARS-CoV-2 polymerase chain reaction (PCR) test on each sample. Statistical analysis of the data was performed using Microsoft Excel and SPSS version 17 software. To determine the sensitivity of the two RDTs, the Bayesian latent class model was performed on the median with a 95% confidence interval with p<0.05 as the significant level. An ethical clearance was sought and obtained from the University of Douala Institutional Ethics Committee.

Results: a total of 1813 participants were included in our study, with a predominance of men (1226, 68.68 %) and the most represented age group was that of 31 to 40 years (568, 31.33 %). Most of the participants were married (888, 53.46%) and only a few had a known COVID-19 status (75, 5.47%). The two rapid tests on our study population show much closed COVID-19 prevalence values, respectively 2.03 for BIOSYNEX COVID-19 Ag BSS and 2.17 for BIOSYNEX COVID-19 Ag + BSS. RDT BIOSYNEX COVID-19 Ag + BSS showed higher sensitivity 94.1% vs. 87.5% for RDT BIOSYNEX COVID-19 Ag BSS with almost identical specificity 98.9% for RDT BIOSYNEX COVID-19 Ag + BSS vs. 98.7% for RDT BIOSYNEX COVID-19 Ag BSS compared to AmpliQuick SARS-CoV-2. BIOSYNEX COVID-19 Ag + BSS RDT showed a negative predictive value of 99.9% compared to BIOSYNEX COVID-19 Ag BSS RDT. There is a 99.9% agreement between the RDT BIOSYNEX COVID-19 Ag BSS and the RDT BIOSYNEX COVID-19 Ag + BSS. : the RDT BIOSYNEXCOVID-19 Ag + BSS and RDT BIOSYNEX COVID-19 Ag BSS can be used for the diagnosis of SARS-CoV-2 and can have an important contribution in the context of mass screenings and screening in remote areas.