Performance and operational feasibility of antigen and antibody rapid diagnostic tests for COVID-19 in symptomatic and asymptomatic patients in Cameroon: a clinical, prospective, diagnostic accuracy study

• Published in: The Lancet infectious diseases Vol. 21; no. 8; pp. 1089 - 1096
• Main Authors: Boum, Yap, Fai, Karl Njuwa, Nikolay, Birgit, Mboringong, Akenji Blaise, Bebell, Lisa M, Ndifon, Mark, Abbah, Aristide, Essaka, Rachel, Eteki, Lucrèce, Luquero, Francisco, Langendorf, Céline, Mbarga, Nicole Fouda, Essomba, Rene Ghislain, Buri, Bongkiyung Donald, Corine, Tchoula Mamiafo, Kameni, Bertrand Tchualeu, Mandeng, Nadia, Fanne, Mahamat, Bisseck, Anne-Cécile Zoung-Kani, Ndongmo, Clement B, Eyangoh, Sara, Hamadou, Achta, Ouamba, Jean Patrick, Koku, Modeste Tamakloé, Njouom, Richard, Claire, Okomo Marie, Esso, Linda, Epée, Emilienne, Mballa, Georges Alain Etoundi
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 01.08.2021; Elsevier B.V; Elsevier Limited
• Subjects: Accuracy; Algorithms; Antibodies; Antibodies, Viral - blood; Antigens; Antigens, Viral - analysis; Asymptomatic; Asymptomatic Infections; Biosensors; Coronaviruses; COVID-19; COVID-19 - diagnosis; COVID-19 Serological Testing; Detectors; Diagnostic systems; Diagnostic tests; Disease transmission; Enzyme-linked immunosorbent assay; Feasibility Studies; Humans; Immunoassays; Infections; Infectious diseases; Laboratories; Medical diagnosis; Medical tests; Pandemics; Patients; Performance assessment; Performance evaluation; Peripheral blood; Prospective Studies; SARS-CoV-2 - immunology; Sensitivity; Sensitivity analysis; Sensitivity and Specificity; Severe acute respiratory syndrome coronavirus 2; Translations; Viral antibodies; Viral diseases; Cameroon; China; Africa
• ISSN: 1473-3099; 1474-4457; 1474-4457
• DOI: 10.1016/S1473-3099(21)00132-8

Real-time PCR is recommended to detect SARS-CoV-2 infection. However, PCR availability is restricted in most countries. Rapid diagnostic tests are considered acceptable alternatives, but data are lacking on their performance. We assessed the performance of four antibody-based rapid diagnostic tests and one antigen-based rapid diagnostic test for detecting SARS-CoV-2 infection in the community in Cameroon. In this clinical, prospective, diagnostic accuracy study, we enrolled individuals aged at least 21 years who were either symptomatic and suspected of having COVID-19 or asymptomatic and presented for screening. We tested peripheral blood for SARS-CoV-2 antibodies using the Innovita (Biological Technology; Beijing, China), Wondfo (Guangzhou Wondfo Biotech; Guangzhou, China), SD Biosensor (SD Biosensor; Gyeonggi-do, South Korea), and Runkun tests (Runkun Pharmaceutical; Hunan, China), and nasopharyngeal swabs for SARS-CoV-2 antigen using the SD Biosensor test. Antigen rapid diagnostic tests were compared with Abbott PCR testing (Abbott; Abbott Park, IL, USA), and antibody rapid diagnostic tests were compared with Biomerieux immunoassays (Biomerieux; Marcy l'Etoile, France). We retrospectively tested two diagnostic algorithms that incorporated rapid diagnostic tests for symptomatic and asymptomatic patients using simulation modelling. 1195 participants were enrolled in the study. 347 (29%) tested SARS-CoV-2 PCR-positive, 223 (19%) rapid diagnostic test antigen-positive, and 478 (40%) rapid diagnostic test antibody-positive. Antigen-based rapid diagnostic test sensitivity was 80·0% (95% CI 71·0–88·0) in the first 7 days after symptom onset, but antibody-based rapid diagnostic tests had only 26·8% sensitivity (18·3–36·8). Antibody rapid diagnostic test sensitivity increased to 76·4% (70·1–82·0) 14 days after symptom onset. Among asymptomatic participants, the sensitivity of antigen-based and antibody-based rapid diagnostic tests were 37·0% (27·0–48·0) and 50·7% (42·2–59·1), respectively. Cohen's κ showed substantial agreement between Wondfo antibody rapid diagnostic test and gold-standard ELISA (κ=0·76; sensitivity 0·98) and between Biosensor and ELISA (κ=0·60; sensitivity 0·94). Innovita (κ=0·47; sensitivity 0·93) and Runkun (κ=0·43; sensitivity 0·76) showed moderate agreement. An antigen-based retrospective algorithm applied to symptomatic patients showed 94·0% sensitivity and 91·0% specificity in the first 7 days after symptom onset. For asymptomatic participants, the algorithm showed a sensitivity of 34% (95% CI 23·0–44·0) and a specificity of 92·0% (88·0–96·0). Rapid diagnostic tests had good overall sensitivity for diagnosing SARS-CoV-2 infection. Rapid diagnostic tests could be incorporated into efficient testing algorithms as an alternative to PCR to decrease diagnostic delays and onward viral transmission. Médecins Sans Frontières WACA and Médecins Sans Frontières OCG. For the French and Spanish translations of the abstract see Supplementary Materials section.