1d). and endemic global context. Keywords: Lateral circulation assay, SARS-CoV-2 IgG, COVID-19, Self-testing, Biomarker, Preconcentration 1.?Intro Lateral circulation assays (LFAs) have demonstrated practical clinical energy as feasible point-of-care screening (POCT) platforms that satisfy most of the World Health Organization’s ASSURED criteria (affordable, sensitive, specific, user-friendly, quick/robust, equipment-free, and deliverable to end users) regarding many self-testing products (we.e., pregnancy, influenza A/B, and malaria diagnostic checks). Moreover, as LFAs use fluidic circulation under capillary action, no external power products (e.g., pumps or centrifuges) is required for device operation. However, commercial LFAs have several limitations, including poorer level of sensitivity and lower specificity compared to those of laboratory checks (e.g., enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR)) (Carter et al., 2020; Udugama et al., 2020; vehicle Kasteren et al., 2020; Wolfel et al., 2020). Study is definitely underway to improve the level of sensitivity and specificity of LFAs to accomplish more accurate and high-performance POCT. Such investigations have primarily focused on assay optimization (reagent and receptor) (Dighe et al., 2022; Garg et al., 2021; Give et al., 2020; Yu et al., 2020; Zhang et al., 2021), transmission amplification (chemical enhancement and electrochemistry and fluorescence reader) (Cheng et al., 2017; Wang et al., 2017, 2021), A-867744 and sample enrichment (magnetic separation and electrokinetic pre-concentration) (Kang et al., 2021; Wang et al., 2021a, Wang et al., 2021b; Zhou et al., 2021) to accomplish high level of sensitivity and selectivity (Dempsey and Rathod, 2018 Han et al., 2020; Jia et al., 2018; Li et al., 2019; Loynachan et al., 2018; Mu A-867744 et al., 2019; Niu et al., 2020, Niu et al., 2021; Ojaghi et al., 2018; Xu et al., 2014). As one of the sample enrichment techniques, our group explained a nanoelectrokinetic (NEK)-centered method for sample enrichment in writing, illustrating that bovine serum albumin (BSA) can be preconcentrated by up to five occasions the initial concentration in serum (Han et al., 2018; Jeong et al., 2018). Further, this method was integrated with the commercial pregnancy LFA to increase the limit of detection (LOD) by 2.69-fold) and analytical sensitivity by 26%, illustrating a linear relationship between these variables (Kim et al., 2017). Most recently, we developed a large-volume preconcentrator (LVP) platform using the NEK concentration technology (Lee et A-867744 al., 2021). Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is currently spreading rapidly worldwide, and the WHO declared the coronavirus disease of 2019 (COVID-19) a pandemic on March 11, 2020 (Chinazzi et al., 2020; Liu et al., 2020; Menni et al., 2020; Salje et al., 2020; Tian et al., 2020; Zhang et al., 2020). In the beginning of 2022, the omicron variant became the dominating variant in many countries since it replicated faster than all other SARS-CoV-2 variants. In the pandemic and endemic period following growth of the omicron variant, a highly sensitive LFA is an ideal candidate for friend diagnostics. For example, fast detection enables immediate treatment with antiviral medicines, such as Paxlovid, for COVID-19 via oral route. In addition, quick MAPK1 and highly sensitive on-site serological assays to measure antibody levels during COVID-19 are extremely important for monitoring immunological reactions to SARS-CoV-2 in various clinical environments. However, the general method incurs high costs due to the required manpower and products, leading to health care inequality in low-income countries (Orach, 2009). To resolve this issue, an A-867744 inexpensive POCT technology is required, and self-testing using paper centered LFA has emerged as a encouraging technology. For example, our study confirmed the applicability of SARS-CoV-2 antibody analysis using an LFA. SARS-CoV-2 antibody screening could provide important info on convalescence from COVID-19, and will likely help determine the level of community immunity, especially in the endemic period after the quick spread of the omicron variant. (R?ltgen et al., 2020; Veldhoen and Simas, 2021). Enzyme-linked immunosorbent assay (ELISA), Automated A-867744 Chemiluminescence Immunoassay (CLIA), LFA, and Microsphere immunoassay (MIA) can detect SARS-CoV-2 antibodies. The important characteristics of ELISA, CLIA, LFA, and MIA, including sample volume, test time, the potential for POCT, as well as others are explained in Table S1. Among them, LFA was fast, inexpensive, and easy to use (ideal for POCT). However, this method offers several limitations, including lower level of sensitivity and specificity than laboratory checks. The sensitivity of the SARS-CoV-2 LFA antibody test is definitely 55% that of RT-PCR and 65% that of ELISA (Blossom et al., 2020; Panel et al.,.