Evaluation of the Omicron variant by RT-PCR and rapid antigen testing (ExacTest™ COVID-19 Antigen Rapid Test)

Abstract

Purpose: The present study aims to compare the results of the COVID-19 rapid antigen test (ExacTest™ COVID-19 Antigen Rapid Test) and real-time polymerase chain reaction (RT-PCR) test in samples of people suspected of coronavirus disease (COVID-19).
Materials and methods: Among the samples submitted between January 2022 and March 2022 with suspicion of COVID-19, 299 samples subject to simultaneous COVID-19 RADT (Rapid Antigen Detection Test) and RT-PCR were evaluated retrospectively. The Real-Time PCR test was studied with the DS CORONEX COVID-19 Multiplex Real time-qPCR Test Kit (DS Nano and Biotechnology Product Tracing and Tracking Co., Turkey) and the rapid antigen test was studied by the immunochromatographic method with ExacTest™ COVID-19 Antigen Rapid Test Cassette kit (General Diagnostica inc., California, USA). Ag-RDT test results were evaluated with the fluorescent immunoassay analyzer (FIATEST Analyzer, Hangzhou Alltest Biotech Co., Ltd. China).
Results: RT-PCR test was positive in 53 (17.7%) samples. The RADT's sensitivity was found 88.7 (95% Cl 77.0-95.7), specificity 98.0 (95% Cl 95.3-99.3), positive predictive value 90.4 (95% Cl 79.7-95.8), negative predictive value 97.6 (95% Cl 95.0-98.8), and accuracy 96.3 (95% Cl 93.5-98.2). Sample sensitivities of patients under and over 18 years of age have been identified as 75 (95% Cl 19.4-99.4) and 89.8 (95% Cl 77.8-96.6), respectively. The sensitivity of patients with and without symptoms was 95.5 (95% Cl 77.2-99.9) and 83.9 (95% Cl 66.3-94.6), respectively. For samples with a cycle threshold (Ct) of <20, 20-<25, 25-<30 and 30-<35, the concordance of testing was 100%, 92.9%, 78.9% and 80%, respectively.
Conclusion: The rapid antigen kit studied complies with the use criteria recommended by the World Health Organization and is quite useful for the rapid diagnosis of symptomatic patients in COVID-19.

Keywords

• COVID-19
• RT-PCR
• RADT
• immunochromatography method

Omicron varyantının RT-PCR ve hızlı antijen testi (ExacTest™ COVID-19 Antijen Hızlı Testi) ile değerlendirilmesi

Abstract

Amaç: Çalışmamızda, koronavirüs hastalığı (COVID-19) şüphesi olan kişilerin örneklerinde COVID-19 hızlı antijen testi (ExacTest™ COVID-19 Antigen Rapid Test) ve gerçek zamanlı polimeraz zincir reaksiyonu (RT-PCR) testi sonuçlarının karşılaştırılması amaçlanmıştır.
Gereç ve yöntem: Ocak 2022-Mart 2022 tarihleri arasında COVID-19 şüphesi ile gönderilen örneklerde eş zamanlı COVID-19 RADT (Rapid Antigen Detection Test) ve RT-PCR çalışılan 299 örnek retrospektif olarak değerlendirilmiştir. Real-Time PCR testi, DS CORONEX COVID-19 Multiplex Real Time-qPCR Test Kiti (DS Nano and Biotechnology Product Tracing and Tracking Co.,Türkiye) ile ve hızlı antijen testi immünokromatografi yöntemi ile ExacTest™ COVID-19 Antigen Rapid Test Cassette (General Diagnostica inc., California, USA) kitiyle çalışılmıştır. RADT testi sonuçları floresan immünoassay analiz cihazı (FIATEST Analyzer, Hangzhou Alltest Bıotech Co.,Ltd. China) ile değerlendirildi.
Bulgular: RT-PCR testi 53 (%17,7) örnekte pozitif olarak saptanmıştır. RADT duyarlılığı 88,7 (%95 Cl 77,0-95,7), özgüllüğü 98,0 (%95 Cl 95,3-99,3), pozitif öngörü değeri 90,4 (%95 Cl 79,7-95,8), negatif öngörü değeri 97,6 (%95 Cl 95,0-98,8) ve doğruluğu 96,3 (%95 Cl 93,5-98,2) olarak bulunmuştur. 18 yaş altı ve 18 yaş ve üstü hastaların örnek duyarlılıkları sırasıyla 75 (%95 Cl 19,4-99,4), 89,8 (%95 Cl 77,8-96,6) olarak tespit edilmiştir. Semptomu olan ve olmayan hastaların duyarlılığı sırasıyla 95,5 (%95 Cl 77,2-99,9), 83,9 (%95 Cl 66,3-94,6) olarak saptanmıştır. Döngü eşiği (Ct) <20, 20-<25, 25-<30, 30-<35 olan örneklerde testin uyumu sırasıyla %100, %92,9, %78,9, %80 olarak bulunmuştur.
Sonuç: Çalışılan hızlı antijen kiti dünya sağlık örgütünün önerdiği kullanılabilirlik kriterleri ile uyumludur ve semptomatik hastaların COVID-19 tanısında hızlı sonuç alınması açısından oldukça yararlıdır.

Keywords

• COVID-19
• RT-PCR
• RADT
• immünokromatografi yöntemi

References

1. 1. World Health Organization (2021). Antigen-detection in the diagnosis of SARS-CoV-2 infection: interim guidance [online]. Website https://apps.who.int/iris/handle/10665/345948 (Erişim tarihi 7 Haziran 2022)
2. 2. World Health Organization (2021). Recommendations for national SARS-CoV-2 testing strategies and diagnostic capacities: interim guidance [online]. Website https://www.who.int/publications/i/item/WHO-2019-nCoV-lab-testing-2021.1-eng (Erişim tarihi 7 Haziran 2022)
3. 3. Drain P, Sulaiman R, Hoppers M, Lindner NM, Lawson V, Ellis JE. Performance of the LumiraDx Microfluidic Immunofluorescence Point-of-Care SARS-CoV-2 Antigen Test in asymptomatic adults and children. Am J Clin Pathol 2022;157:602-607. doi: 10.1093/ajcp/aqab173
4. 4. Wölfl-Duchek M, Bergmann F, Jorda A, Weber M, Müller M, Seitz T, et al. Sensitivity and specificity of SARS-COV-2 rapid antigen detection tests using oral, anterior nasal, and nasopharyngeal swabs: a diagnostic accuracy study. Microbiol Spectr 2022;10:e0202921. doi: 10.1128/spectrum.02029-21
5. 5. Elli S, Blasi F, Brignolo B, Ceriotti F, Gori A, Piatti A, et al. Diagnostic accuracy of rapid antigen test for COVID-19 in an emergency department. Diagn Microbiol Infect Dis 2022;102:115635. doi: 10.1016/j.diagmicrobio.2022.115635
6. 6. Jääskeläinen AE, Ahava MJ, Jokela P, Szirovicza L, Pohjala S, Vapalahti O, et al. Evaluation of three rapid lateral flow antigen detection tests for the diagnosis of SARS-CoV-2 infection. J Clin Virol 2021;137:104785. doi: 10.1016/j.jcv.2021.104785
7. 7. Lau CS, Aw TC. Disease prevalence matters: Challenge for SARS-CoV-2 testing. Antibodies (Basel) 2021;10:50. doi: 10.3390/antib10040050
8. 8. Khalid MF, Selvam K, Jeffry AJN, Salmi MF, Najib MA, Norhayati MN, et al. Performance of rapid antigen tests for COVID-19 diagnosis: A systematic review and meta-analysis. Diagnostics (Basel) 2022;12:110. doi: 10.3390/diagnostics12010110

9. 9. World Health Organization (2020). SARS-CoV-2 Antigen-Detecting Rapid Diagnostic Tests: An Implementation Guide [online]. Website https://www.who.int/publications/i/item/9789240017740 (Erişim tarihi 10 Haziran 2022)
10. 10. Turcato G, Zaboli A, Pfeifer N, Sibilio S, Tezza G, Bonora A, et al. Rapid antigen test to identify COVID-19 infected patients with and without symptoms admitted to the Emergency Department. Am J Emerg Med 2022;51:92-97. doi: 10.1016/j.ajem.2021.10.022
11. 11. Torres I, Poujois S, Albert E, Álvarez G, Colomina J, Navarro D. Point-of-care evaluation of a rapid antigen test (CLINITESTⓇ Rapid COVID-19 Antigen Test) for diagnosis of SARS-CoV-2 infection in symptomatic and asymptomatic individuals. J Infect 2021;82:e11-2. doi: 10.1016/j.jinf.2021.02.010
12. 12. Chiu RYT, Kojima N, Mosley GL, Cheng KK, Pereira DY, Brobeck M, et al. Evaluation of the INDICAID COVID-19 rapid antigen test in symptomatic populations and asymptomatic community testing. Microbiol Spectr 2021;9:e0034221. doi: 10.1128/Spectrum.00342-21
13. 13. Siddiqui ZK, Chaudhary M, Robinson ML, McCall AB, Peralta R, Esteve R, et al. Implementation and accuracy of BinaxNOW Rapid Antigen COVID-19 Test in asymptomatic and symptomatic populations in a high-volume self-referred testing site. Microbiol Spectr 2021;9:e0100821. doi: 10.1128/Spectrum.01008-21
14. 14. Mitchell SL, Orris S, Freeman T, Freeman MC, Adam M, Axe M, et al. Performance of SARS-CoV-2 antigen testing in symptomatic and asymptomatic adults: a single-center evaluation. BMC Infect Dis 2021;21:1071. doi: 10.1186/s12879-021-06716-1
15. 15. de Michelena P, Torres I, Ramos-García Á, Gozalbes V, Ruiz N, Sanmartín A, et al. Real-life performance of a COVID-19 rapid antigen detection test targeting the SARS-CoV-2 nucleoprotein for diagnosis of COVID-19 due to the Omicron variant. J Infect 2022;84:e64-6. doi: 10.1016/j.jinf.2022.02.022
16. 16. Albert E, Torres I, Bueno F, Huntley D, Molla E, Fernández-Fuentes MÁ, et al. Field evaluation of a rapid antigen test (Panbio™ COVID-19 Ag Rapid Test Device) for COVID-19 diagnosis in primary healthcare centres. Clin Microbiol Infect 2021;27:472.e7-472.e10. doi: 10.1016/j.cmi.2020.11.004
17. 17. Favresse J, Gillot C, Oliveira M, Cadrobbi J, Elsen M, Eucher C, et al. Head-to-head comparison of rapid and automated antigen detection tests for the diagnosis of SARS-CoV-2 infection. J Clin Med 2021;10:265. doi: 10.3390/jcm10020265
18. 18. Brümmer LE, Katzenschlager S, Gaeddert M, Erdmann C, Schmitz S, Bota M, et al. Accuracy of novel antigen rapid diagnostics for SARS-CoV-2: A living systematic review and meta-analysis. PLoS Med 2021;18:e1003735. doi: 10.1371/journal.pmed.1003735
19. 19. Ford L, Lee C, Pray IW, Cole D, Bigouette JP, Abedi GR, et al. Epidemiologic characteristics associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigen-based test results, real-time reverse transcription polymerase chain reaction (rRT-PCR) cycle threshold values, subgenomic RNA, and viral culture results from university testing. Clin Infect Dis 2021;73:e1348-55. doi: 10.1093/cid/ciab303
20. 20. Kanaujia R, Ghosh A, Mohindra R, Singla V, Goyal K, Gudisa R, et al. Rapid antigen detection kit for the diagnosis of SARS-CoV-2 - are we missing asymptomatic patients? Indian J Med Microbiol 2021;39:457-61. doi: 10.1016/j.ijmmb.2021.07.003
21. 21. Yang YP, Huang LL, Pan SJ, Xu D, Jiesisibieke ZL, Tung TH. False-positivity results in rapid antigen tests for SARS-CoV-2: an umbrella review of meta-analyses and systematic reviews. Expert Rev Anti Infect Ther 2022;1-9. doi: 10.1080/14787210.2022.2070152