ABSTRACT
A rapid, sensitive and simple microflow cytometry-based agglutination immunoassay (MCIA) was developed for point-of-care (POC) quantitative detection of SARS-CoV-2 IgM and IgG antibodies. The antibody concentration was determined by using the transit time of beads aggregates. A linear relationship was established between the average transit time and the concentration of SARS-CoV-2 IgM and IgG, respectively. The limit of detection (LOD) of SARS-CoV-2 IgM and IgG by the MCIA measurement are 0.06 mg/L and 0.10 mg/L, respectively. The 10 µL sample consumption, 30 min assay time and the compact setup make this technique suitable for POC quantitative detection of SARS-CoV-2 antibodies.
ABSTRACT
An accurate and rapid microflow cytometry-based agglutination immunoassay (MCIA) suitable for on-site antibody or antigen detection was proposed. In this study, quantitative C-reactive protein (CRP) detection was chosen as a model assay in order to demonstrate the detection principle. The average transit time was employed to estimate the extent of the agglutination reaction and improve the detection accuracy as compared to the intensity-dependent methods. The detection time was less than 8 min. and only a 20 µL serum sample was needed for each test. The results showed a linear relationship between the average transit time of aggregates and CRP concentrations ranging from 0 to 1 µg/mL. The R2 of this relationship was 0.99. The detection limit of this technology was 0.12 µg/mL CRP. The system used for CRP detection can be extended to also monitor other clinically relevant molecules.
