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In-Depth Longitudinal Comparison of Clinical Specimens to Detect SARS-CoV-2

Department of Clinical Microbiology, University of Liège, 4000 Liège, Belgium
Department of Infectious Diseases, Liège University Hospital, 4000 Liège, Belgium
Laboratory of Cellular and Molecular Immunology, GIGA Institute, University of Liège, 4000 Liège, Belgium
Immunology-Vaccinology Laboratory, Department of Infectious and Parasitic Diseases, FARAH, University of Liège, 4000 Liège, Belgium
Unit of Animal Genomics, GIGA Institute, University of Liège, 4000 Liège, Belgium
Biostatistics and Medico-Economic Information Department, University Hospital of Liege, 4000 Liege, Belgium
Author to whom correspondence should be addressed.
Academic Editors: Luis Martinez-Sobrido and Marta L. DeDiego
Pathogens 2021, 10(11), 1362;
Received: 31 August 2021 / Revised: 13 October 2021 / Accepted: 18 October 2021 / Published: 21 October 2021
(This article belongs to the Collection SARS-CoV-2 Infection and COVID-19 Disease)
The testing and isolation of patients with coronavirus disease 2019 (COVID-19) are indispensable tools to control the ongoing COVID-19 pandemic. PCR tests are considered the “gold standard” of COVID-19 testing and mostly involve testing nasopharyngeal swab specimens. Our study aimed to compare the sensitivity of tests for various sample specimens. Seventy-five participants with confirmed COVID-19 were included in the study. Nasopharyngeal swabs, oropharyngeal swabs, Oracol-collected saliva, throat washes and rectal specimens were collected along with pooled swabs. Participants were asked to complete a questionnaire to correlate specific clinical symptoms and the symptom duration with the sensitivity of detecting COVID-19 in various sample specimens. Sampling was repeated after 7 to 10 days (T2), then after 14 to 20 days (T3) to perform a longitudinal analysis of sample specimen sensitivity. At the first time point, the highest percentages of SARS-CoV-2-positive samples were observed for nasopharyngeal samples (84.3%), while 74%, 68.2%, 58.8% and 3.5% of throat washing, Oracol-collected saliva, oropharyngeal and rectal samples tested positive, respectively. The sensitivity of all sampling methods except throat wash samples decreased rapidly at later time points compared to the first collection. The throat washing method exhibited better performance than the gold standard nasopharyngeal swab at the second and third time points after the first positive test date. Nasopharyngeal swabs were the most sensitive specimens for early detection after symptom onset. Throat washing is a sensitive alternative method. It was found that SARS-CoV-2 persists longer in the throat and saliva than in the nasopharynx. View Full-Text
Keywords: COVID-19; SARS-CoV-2; diagnosis; persistence COVID-19; SARS-CoV-2; diagnosis; persistence
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MDPI and ACS Style

Defêche, J.; Azarzar, S.; Mesdagh, A.; Dellot, P.; Tytgat, A.; Bureau, F.; Gillet, L.; Belhadj, Y.; Bontems, S.; Hayette, M.-P.; Schils, R.; Rahmouni, S.; Ernst, M.; Moutschen, M.; Darcis, G. In-Depth Longitudinal Comparison of Clinical Specimens to Detect SARS-CoV-2. Pathogens 2021, 10, 1362.

AMA Style

Defêche J, Azarzar S, Mesdagh A, Dellot P, Tytgat A, Bureau F, Gillet L, Belhadj Y, Bontems S, Hayette M-P, Schils R, Rahmouni S, Ernst M, Moutschen M, Darcis G. In-Depth Longitudinal Comparison of Clinical Specimens to Detect SARS-CoV-2. Pathogens. 2021; 10(11):1362.

Chicago/Turabian Style

Defêche, Justine, Samira Azarzar, Alyssia Mesdagh, Patricia Dellot, Amandine Tytgat, Fabrice Bureau, Laurent Gillet, Yasmine Belhadj, Sebastien Bontems, Marie-Pierre Hayette, Raphaël Schils, Souad Rahmouni, Marie Ernst, Michel Moutschen, and Gilles Darcis. 2021. "In-Depth Longitudinal Comparison of Clinical Specimens to Detect SARS-CoV-2" Pathogens 10, no. 11: 1362.

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