Conference abstract
Excellent performance of INDICAIDTM antigen rapid diagnostic test on COVID-19 clinical samples with moderate-high viral loads during the Omicron epidemiological wave in Cameroon
Pan African Medical Journal - Conference Proceedings. 2023:18(8).03
Oct 2023.
doi: 10.11604/pamj-cp.2023.18.8.2053
Archived on: 03 Oct 2023
Contact the corresponding author
Keywords: Antigene detection, INDICAIDTM Ag-RDT, RT-PCR, SARS-CoV-2
Oral presentation
Excellent performance of INDICAIDTM antigen rapid diagnostic test on COVID-19 clinical samples with moderate-high viral loads during the Omicron epidemiological wave in Cameroon
Fokam Joseph1,&, Takou Desire1, Ngoufack Ezechiel1, Chenwi Collins1, Molimbou Evariste1, Djupsa Sandrine1, Moko Larissa1, Otshudiema Otokoye John2, Djubgang Djoukwe R3, Okomo Assoumou MC4, Yap Boum III5, Mballa Etoundi GA5, Nka Alex1, Ka’e Aude1, Beloumou Grace1, Gouissi Davy1, Nayan Audrey1, Kengni Aurelie1, Etame Naomi-K1, Aissatou Abba1, Teto Goerges1, Dambaya Beatrice1, Tchouaket Michel1, Bouba Yangai1, Fainguem Nadine1, Carlo-Federico Perno6, Vittorio Colizzi6, Alexis Ndjolo1
1Chantal Biya International Reference Centre for research on HIV/AIDS prevention and management, Yaounde, Cameroon, 2World Health Organisation, Afro, Country office, Yaounde, Cameroon, 3Directorate for Pharmacy, Drug and Laboratory, Ministry of Public Health, Yaounde, Cameroon, 4National Public Health Laboratory, Yaounde, Cameroon, 5National Public Health Emergency Operations Centre, Ministry of Public Health, Yaounde,Cameroon, 6University of Rome “Tor Vergata”, Rome, Italy
&Corresponding author
Introduction: the World Health Organisation recommends the use of COVID-19 antigen rapid diagnostic tests (AgRDT) with at least 80% sensitivity and 97% specificity. In the era of Omicron variants harboring several mutations in the viral genes, we sought to ascertain the performance of INDICAIDTM COVID-19 AgRDT with reference to PCR. The objectivewas to evaluate the performance of the INDICAIDTM rapid diagnostic test on COVID-19 clinical specimens with moderate or elevated viral load at the Omicron variants era.
Methods: an observational laboratory-based study was conducted from March to August 2022 among consenting individuals tested for SARS-CoV-2 infection at the Virology laboratory of the Chantal BIYA International Reference Centre, Yaounde-Cameron. Nasopharyngeal samples were processed both on INDICAIDTM COVID-19 AgRDT and on DaAn Gene real-time PCR as per national guidelines. Sensitivity, specificity, and positive and negative predictive values of INDICAIDTM COVID-19 RDT were evaluated according to viral load; with p<0.05 considered statistically significant.
Results: out of 565 nasopharyngeal swabs collected, aged ≥21 years, the positivity rate was 5.6%(32) with RT-PCR versus 1.24%(7) with INDICAIDTM COVID-19 AgRDT, p<0.0001. At PCR CT<37, (mean CT=33.1±3.86), sensitivity INDICAIDTM COVID-19 Ag-RDT was 21.9% (95%CI:[12.5–21.9]); specificity was 100% (95%CI:[99.4–100]); kappa=0.832 ([95%CI: 0.422-0.832]), positive predictive value was 100%(95%CI: [57.3–100]) and negative predictive value was 95.5% (95%CI:[95– 95.5]). At PCR CT<25, (mean CT=21.2±2.34), sensitivity was 100%(95%CI:[51.3–100.0]); specificity was 99.6% (95% CI:[99.2–99.6]); kappa=0.346 (95%CI:[0.189–0.346]), positive predictive value was 71.4%(95% CI: [36.7–71.4]) and negative predictive value was 97.7%(95%CI:[97.1–97.7]). COVID-19 sequences generated were all Omicron sub-variant BA.1.
Conclusion: for patients infected with moderate-high viral loads, INDICAIDTM Ag-RDT has high intrinsic (sensitivity and specificity) and extrinsic (predictive values) performances for the diagnosis of COVID-19. With its simplicity and short turn-around-time (15±2min), INDICAIDTM COVID-19 Ag-RDT is a reliable tool to prevent the spread of COVID-19 at community-level, in the era of Omicron variants.
Excellent performance of INDICAIDTM antigen rapid diagnostic test on COVID-19 clinical samples with moderate-high viral loads during the Omicron epidemiological wave in Cameroon
Fokam Joseph1,&, Takou Desire1, Ngoufack Ezechiel1, Chenwi Collins1, Molimbou Evariste1, Djupsa Sandrine1, Moko Larissa1, Otshudiema Otokoye John2, Djubgang Djoukwe R3, Okomo Assoumou MC4, Yap Boum III5, Mballa Etoundi GA5, Nka Alex1, Ka’e Aude1, Beloumou Grace1, Gouissi Davy1, Nayan Audrey1, Kengni Aurelie1, Etame Naomi-K1, Aissatou Abba1, Teto Goerges1, Dambaya Beatrice1, Tchouaket Michel1, Bouba Yangai1, Fainguem Nadine1, Carlo-Federico Perno6, Vittorio Colizzi6, Alexis Ndjolo1
1Chantal Biya International Reference Centre for research on HIV/AIDS prevention and management, Yaounde, Cameroon, 2World Health Organisation, Afro, Country office, Yaounde, Cameroon, 3Directorate for Pharmacy, Drug and Laboratory, Ministry of Public Health, Yaounde, Cameroon, 4National Public Health Laboratory, Yaounde, Cameroon, 5National Public Health Emergency Operations Centre, Ministry of Public Health, Yaounde,Cameroon, 6University of Rome “Tor Vergata”, Rome, Italy
&Corresponding author
Introduction: the World Health Organisation recommends the use of COVID-19 antigen rapid diagnostic tests (AgRDT) with at least 80% sensitivity and 97% specificity. In the era of Omicron variants harboring several mutations in the viral genes, we sought to ascertain the performance of INDICAIDTM COVID-19 AgRDT with reference to PCR. The objectivewas to evaluate the performance of the INDICAIDTM rapid diagnostic test on COVID-19 clinical specimens with moderate or elevated viral load at the Omicron variants era.
Methods: an observational laboratory-based study was conducted from March to August 2022 among consenting individuals tested for SARS-CoV-2 infection at the Virology laboratory of the Chantal BIYA International Reference Centre, Yaounde-Cameron. Nasopharyngeal samples were processed both on INDICAIDTM COVID-19 AgRDT and on DaAn Gene real-time PCR as per national guidelines. Sensitivity, specificity, and positive and negative predictive values of INDICAIDTM COVID-19 RDT were evaluated according to viral load; with p<0.05 considered statistically significant.
Results: out of 565 nasopharyngeal swabs collected, aged ≥21 years, the positivity rate was 5.6%(32) with RT-PCR versus 1.24%(7) with INDICAIDTM COVID-19 AgRDT, p<0.0001. At PCR CT<37, (mean CT=33.1±3.86), sensitivity INDICAIDTM COVID-19 Ag-RDT was 21.9% (95%CI:[12.5–21.9]); specificity was 100% (95%CI:[99.4–100]); kappa=0.832 ([95%CI: 0.422-0.832]), positive predictive value was 100%(95%CI: [57.3–100]) and negative predictive value was 95.5% (95%CI:[95– 95.5]). At PCR CT<25, (mean CT=21.2±2.34), sensitivity was 100%(95%CI:[51.3–100.0]); specificity was 99.6% (95% CI:[99.2–99.6]); kappa=0.346 (95%CI:[0.189–0.346]), positive predictive value was 71.4%(95% CI: [36.7–71.4]) and negative predictive value was 97.7%(95%CI:[97.1–97.7]). COVID-19 sequences generated were all Omicron sub-variant BA.1.
Conclusion: for patients infected with moderate-high viral loads, INDICAIDTM Ag-RDT has high intrinsic (sensitivity and specificity) and extrinsic (predictive values) performances for the diagnosis of COVID-19. With its simplicity and short turn-around-time (15±2min), INDICAIDTM COVID-19 Ag-RDT is a reliable tool to prevent the spread of COVID-19 at community-level, in the era of Omicron variants.
