Clinical sensitivity and specificity of a high-throughput microfluidic nano-immunoassay combined with capillary blood microsampling for the identification of anti-SARS-CoV-2 Spike IgG serostatus

PLOS ONE RESEARCH ARTICLE Clinical sensitivity and specificity of a highthroughput microfluidic nano-immunoassay combined with capillary blood microsampling for the identification of anti-SARS-CoV-2 Spike IgG serostatus a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 OPEN ACCESS Citation: Michielin G, Arefi F, Puhach O, Bellon M, Sattonnet-Roche P, L’Huillier AG, et al. (2023) Clinical sensitivity and specificity of a highthroughput microfluidic nano-immunoassay combined with capillary blood microsampling for the identification of anti-SARS-CoV-2 Spike IgG serostatus. PLoS ONE 18(3): e0283149. https:// doi.org/10.1371/journal.pone.0283149 Grégoire Michielin ID1, Fatemeh Arefi1, Olha Puhach2, Mathilde Bellon2, Pascale SattonnetRoche2, Arnaud G. L’Huillier3,4, Isabella Eckerle3,5,6☯*, Benjamin Meyer7☯*, Sebastian J. Maerkl ID1☯* 1 Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 2 Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland, 3 Laboratory of Virology, Division of Laboratory Medicine, Geneva University Hospitals and Faculty of Medicine, Geneva, Switzerland, 4 Pediatric Infectious Diseases Unit, Department of Woman, Child and Adolescent Medicine, Geneva University Hospitals and Faculty of Medicine, Geneva, Switzerland, 5 Division of Infectious Diseases, Department of Medicine, Geneva University Hospitals and Faculty of Medicine, Geneva, Switzerland, 6 Center for Emerging Viral Diseases, Geneva University Hospitals & Faculty of Medicine, Université de Genève, Geneva, Switzerland, 7 Centre for Vaccinology, Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland ☯ These authors contributed equally to this work. * (IE); (BM); (SJM) Abstract Editor: Basant Giri, Kathmandu Institute of Applied Sciences, NEPAL Received: November 9, 2022 Accepted: March 2, 2023 Published: March 23, 2023 Copyright: © 2023 Michielin et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All relevant data are within the paper and its Supporting Information files. Funding: SJM, IE, and BM received funding from Swiss National Science Foundation COVID-19 NRP-78 grant number 198412 (www.snf.ch). IE received funding from the Private Foundation of the Geneva University Hospital (www.fondationhug. org). The funders had no role in study design, data Objectives We evaluate the diagnostic performance of dried blood microsampling combined with a high-throughput microfluidic nano-immunoassay (NIA) for the identification of anti-SARSCoV-2 Spike IgG seropositivity. Methods We conducted a serological study among 192 individuals with documented prior SARSCoV-2 infection and 44 SARS-CoV-2 negative individuals. Participants with prior SARSCoV-2 infection had a long interval of 11 months since their qRT-PCR positive test. Serum was obtained after venipuncture and tested with an automated electrochemiluminescence anti-SARS-CoV-2 S total Ig reference assay, a commercial ELISA anti-S1 IgG assay, and the index test NIA. In addition, 109 participants from the positive cohort and 44 participants from the negative cohort participated in capillary blood collection using three microsampling devices: Mitra, repurposed glucose test strips, and HemaXis. Samples were dried, shipped by regular mail, extracted, and measured with NIA. PLOS ONE | https://doi.org/10.1371/journal.pone.0283149 March 23, 2023 1 / 16 PLOS ONE collection and analysis, decision to publish, or preparation of the manuscript. Competing interests: The automated DBS extraction was performed using an instrument loaned free of charge by Gerstel AG. Gerstel AG did not take part in the decision to publish the study and did not have editorial control of the results presented. This does not alter our adherence to PLOS ONE policies on sharing data and materials. SARS-CoV-2 IgG high-throughput microfluidic nano-immunoassay combined with capillary blood microsampling Results Using serum samples, we achieve a clinical sensitivity of 98�33% and specificity of 97�62% on NIA, affirming the high performance of NIA in participants 11 months post infection. Combining microsampling with NIA, we obtain a clinical sensitivity of 95�05% using Mitra, 61�11% using glucose test strips, 83�16% using HemaXis, and 91�49% for HemaXis after automated extraction, without any drop in specificity. Discussion High sensitivity and specificity was demonstrated when testing micro-volume capillary dried blood samples using NIA, which is expected to facilitate its use in large-scale studies using home-based sampling or samples collected in the field. Introduction After its appearance in 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) rapidly caused a global pandemic of coronavirus disease of 2019 (COVID-19), totaling over 500 million declared cases as of spring 2022 [1]. Serosurveillance was quickly recognized as an important tool to better understand the evolution of the pandemic and inform public health decisions [2]. The first published results for SARS- CoV-2 seroprevalence studies were from Stringhini et al. describing the seroprevalence after the first wave of the pandemic in the population of Geneva [3]. Also, a coordinated nationwide serosurveillance program called Corona Immunitas helps gather critical data on the SARS-CoV-2 epidemiological situation in Switzerland [4]. Similar serological surveillance programs were conducted in France [5], Netherlands [6], India [7], and the United States of America [8], among others [9]. In order to facilitate such serological surveys, and in particular when proposing longitudinal or repeat testing, it is critical to reduce the burden on study participants as much as possible by simplifying blood sampling and avoiding unnecessary visits to testing centers, while less invasive sampling is especially important when including children into such surveys. However, many serological surveys still rely on a visit to a healthcare center or testing facility where venous blood draws are obtained. Visits to central care facilities could present the participants and staff with a risk of infection. Moreover, some populations are difficult to include during an epidemic or pandemic when such serosurveys are of utmost importance, due to their limited access to proper facilities or due to possible vulnerabilities, such as persons living in elderly care facilities. When large-scale serosurveillance programs are conducted, costs associated with sampling, sample preparation, samples shipping, and analysis also become important parameters. Capillary blood microsampling offers the possibility to decentralize blood collection by untrained individuals, (...truncated)