Further, tests were carried out by laboratory technicians experienced in RDT evaluations, which may possess increased the observations of very faint test lines

Further, tests were carried out by laboratory technicians experienced in RDT evaluations, which may possess increased the observations of very faint test lines. 7.5%, respectively. Cross-reactivity for current and recent malaria, malaria antibodies, varieties and parasite densities was related. Cross-reactivity among the different RDT products ranged from 2.7% to 48.9% (median value 14.5%). IgM displayed 67.9% of cross-reactive test lines. Cross-reactivity was not associated with detecting antigens, patient groups or disease (sub)organizations, except for schistosomiasis (two products with 60% cross-reactivity). The high cross-reactivity for malaria, schistosomiasis andto a lesser extentdengue calls for risk mitigation when using COVID-19 Ab RDTs in co-endemic areas. Keywords: SARS-CoV-2, COVID-19, cross-reactivity 1. Intro COVID-19 antibodies confirm current and past illness by SARS-CoV-2 illness. COVID-19 Ab diagnostics have limited relevance for individual patient care [1,2,3,4], but are important at the public health level for seroprevalence studies. Seroprevalence studies provide information about the extent of the epidemic, case fatality rates Hexacosanoic acid and the risk organizations affected [1,2,3,4,5,6]. A plethora of COVID-19 Ab Detecting Rapid Diagnostic Checks (COVID-19 Ab RDTs) are marketedat the time of writing (May, 2021), the diagnostic tracker of the Foundation of Innovative Diagnostics (Get) lists 213 products [7]; most are lateral-flow immunoassays (LFA) based on a nitrocellulose reagent strip housed inside a plastic cassette. Compared to laboratory platforms (enzyme immunoassays (EIA) and chemiluminescence assays (CLIA)), COVID-19 Ab RDTs have simple logistics, require relatively little training, have a short turnaround time, are easily scalable and are amenable to self-testing. As such, they may Rabbit polyclonal to AGAP1 be consequently desired tools for seroprevalence studies [5,8,9], despite the fact that the WHO recommends the Hexacosanoic acid use of enzyme immunoassays for seroprevalence studies [1]. In low- and middle-income countries (LMICs), COVID-19 Ab RDTs have also been deployed for triage, analysis and contact tracing [10,11,12]. Specificity screening of COVID-19 Ab RDTs so far has focused on seasonal coronaviruses (NL63, HKU1, 229E, OC43), SARS-CoV, cytomegalovirus, EpsteinCBarr disease, human being hepatitis B disease, and parvovirus illness in addition to interfering conditions (rheumatoid element, autoimmune pathologies and hyperglobulinemia) [8,13,14,15,16,17,18,19,20,21,22,23,24,25,26]. Tropical diseases such as malaria, dengue, schistosomiasis and human being African trypanosomiasis are well-known for their cross-reactivity with HIV-1 antibody LFA RDTs and malaria antigen RDTs [27,28,29,30]. The World Health Corporation (WHO) has outlined malaria and dengue among the organisms to be tested for cross-reactivity of COVID-19 serological checks [31,32]. The present study assesses COVID-19 Ab RDTs for cross-reactions when challenged with pre-pandemic samples of individuals with malaria, schistosomiasis and dengue. 2. Materials and Methods This retrospective research study was carried out from the WHO Collaborating Centre for HIV/AIDS Diagnostics and Laboratory Support and (re) growing viral infections and Hexacosanoic acid malaria (BEL-27) in the Institute of Tropical Medicine (ITM), Belgium. COVID-19 Ab RDTs were selected based on design (LFA platform, visual reading), regulatory authorization, independent product evaluations [33,34] and representation of different detecting antigens. A comparator enzyme immune assay detecting IgG and IgM antibodies was selected based on the low required sample volume (10 L) and independent detection of IgG and IgM. In the stage of selection and procurement, the only EIA product available that met both criteria was the DiaPro IgG and IgM EIA (Release Diagnostics Ltd., Sesto San Giovanni, Italy). Table 1 lists the products, manufacturers, detecting antigens used, claimed specimen type and the shortened product names used in the text. Supplementary Table S1 provides full information about the products. Most manufacturers experienced only one lot available, and screening was limited to a single lot per product. Table 1 Overview of different COVID-19 antibody detecting products and EIA relating to manufacturer, targeted antigens (S = spike, N = nucleocapsid, RBD = receptor binding website) and different test lines (IgG and/or IgM). Underlined terms show the abbreviation used in the text. EIA refers to enzyme immunoassay. Wantai RDT product has a solitary test collection, no information was given about the class of antibodies recognized (ND = no data). Claimed specimen: S = serum, P = plasma, WB = whole blood. species, a range of different parasite densities of and disease subgroups (current and recent malaria, presence of malaria antibodies). Honest clearance was Hexacosanoic acid from the Institutional Review Table of ITM (06-2020) and the samples were authorized and stored in the ITM Biobank, according to the Belgian Biobank legislation (06-2020). Table 2 Meanings, total numbers of sample specimens (EDTA whole blood/serum), origin, patient type, age and gender per disease. Research screening and meanings for malaria, dengue and schistosomiasis samples were based on earlier studies [27,35,36,37]. Abbreviations: HRP-2 Ag = histidine-rich protein 2 antigen, IFA = immunofluorescence assay, IQR = inter-quartile range, EIA = enzyme.