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Determination of human COVID‐19 total antibodies in serum using a time‐resolved fluorescence immunoassay
Author(s) -
Xu Yunjian,
Chen Cuicui,
Lai Hongrui,
He Ying,
Guo Guiling,
Feng Jianming,
Li Laiqing
Publication year - 2022
Publication title -
biotechnology and applied biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.468
H-Index - 70
eISSN - 1470-8744
pISSN - 0885-4513
DOI - 10.1002/bab.2219
Subject(s) - immunoassay , covid-19 , antibody , virology , fluorescence , chromatography , biology , chemistry , microbiology and biotechnology , medicine , immunology , pathology , outbreak , infectious disease (medical specialty) , physics , quantum mechanics , disease
Abstract Coronavirus disease 2019 (COVID‐19) caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) is spreading rapidly around the world. Antibody detection plays an important role in the diagnosis of COVID‐19. Here, we established a new time‐resolved fluorescence immunoassay (TRFIA) to determine COVID‐19 total antibodies. A double‐antigen sandwich TRFIA was optimized and established: recombinant nucleocapsid phosphoprotein (N protein) and spike protein (S protein) of COVID‐19 immobilized on 96‐well plates captured human COVID‐19 antibodies and then banded together with the N/S proteins labeled with europium(III) (Eu 3+ ) chelates, and finally, time‐resolved fluorometry was used to measure the fluorescence values. We successfully established a TRFIA method for the detection of human COVID‐19 total antibodies, and the cutoff value was 2.02. There was no cross‐reactivity with the negative reference of the National Reference Panel for IgM and IgG antibodies to COVID‐19. The CV of the precision assay was 3.19%, and the assay could be stored stably for 15 days at 37°C. Compared with that of the colloidal gold method and chemiluminescence method, the sensitivity of the TRFIA method was higher, and the false positive/negative rate was lower. This established TRFIA has high sensitivity, accuracy, and specificity, which indicates that this method provides a new detection method for the high‐throughput routine diagnosis of COVID‐19.