Diagnostic performance of antigen test for the detection of SARS-CoV-2 among patients presenting with COVID-19 symptoms at Bugando Medical Centre

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is a global public health threat causing Coronavirus Disease-2019 (COVID-19). The World Health Organization approved reverse transcriptase polymerase chain reaction (RT-PCR) as a gold standard for the detection of SARS-CoV-2. RT-PCR requires high technology and well-trained personnel, hindering its applicability in low-health care facilities. We evaluated the diagnostic performance of an antigen rapid diagnostic test (Ag-RDT) in detecting SARS-CoV-2 infection among patients presenting with COVID-19 symptoms at Bugando Medical Centre in Mwanza, Tanzania. This laboratory-based cross-sectional study involving 503 COVID-19 suspects was conducted in Mwanza between May 2022 and August 2022. The samples were tested by the RT-PCR and RADI COVID-19 Ag-RDT. Of 98 (20%) samples tested positive for both RT-PCR and Ag-RDT, 379 (75%) tested negative for both RT-PCR. The overall diagnostic performance of Ag-RDT showed 79.0% sensitivity and 100% specificity. During the early stage of cough with fever (≤ 4 days), Ag-RDT showed a high sensitivity of 86.1%. Ag-RDT can be used with much confidence in screening for SARS-CoV-2 infection in individuals presenting with a combination of cough and fever within the first four days of infection and cough was significantly associated with a positive Ag-RDT (p = 0.008).