Background Quantitative point-of-care testing assay for detecting antibodies is critical to COVID-19 control. In this study, we established an up-conversion phosphor technology-based point-of-care testing (UPT-POCT), a lateral flow assay, for rapid COVID-19 diagnosis, as well as prediction of seral neutralizing antibody (NAb) activity and protective effects. Methods UPT-POCT was developed targeting total antibodies against the receptor-binding domain (RBD) of SARS-CoV-2 spike protein. Using ELISA as a contrast method, we evaluated the quantitation accuracy with NAb and serum samples. Cutoff for serum samples was determined through 70 healthy and 140 COVID-19 patients. We evaluated the cross-reactions with antibodies against other viruses. Then, we performed multi-center clinical trials of UPT-POCT, including 782 patients with 387 clinically confirmed COVID-19 cases. Furthermore, RBD-specific antibody levels were detected using UPT-POCT and microneutralization assay for samples from both patients and vaccinees. Specifically, the antibodies of recovered patients with recurrent positive (RP) reverse transcriptase-polymerase chain reaction test results were discussed. Results The ratios of signal intensities between the test and control bands on the lateral flow strip, namely, T/C ratios, was defined as the results of UPT-POCT. T/C ratios had excellent correlations with concentrations of NAb, as well as OD values of ELISA for serum samples. The sensitivity and specificity of UPT-POCT were 89.15% and 99.75% for 782 cases in seven hospitals in China, respectively. We evaluated RBD-specific antibodies for 528 seral samples from 213 recovered and 99 RP COVID-19 patients, along with 35 seral samples from inactivated SARS-CoV-2 vaccinees, and we discovered that the total RBD-specific antibody level indicated by T/C ratios of UPT-POCT was significantly related to the NAb titers in both COVID-19 patients ( r = 0.9404, n = 527; ρ = 0.6836, n = 528) and the vaccinees ( r = 0.9063, ρ = 0.7642, n = 35), and it was highly relevant to the protection rate against RP ( r = 0.9886, n = 312). Conclusion This study reveals that the UPT-POCT for quantitative detection of total RBD-specific antibody could be employed as a surrogate method for rapid COVID-19 diagnosis and prediction of protective effects. Supplementary Information The online version contains supplementary material available at 10.1186/s12866-022-02450-z.
【저자키워드】 COVID-19, clinical trial, Up-conversion phosphor technology, RBD-specific total antibodies, Neutralizing activity, Protective effects, 【초록키워드】 viruses, neutralizing antibody, SARS-CoV-2, antibody, hospital, ELISA, Spike protein, lateral flow, China, point-of-care, lateral flow strip, Protective effects, Microneutralization assay, Receptor-binding domain, Polymerase chain reaction test, Accuracy, Sensitivity and specificity, RBD, SARS-CoV-2 spike protein, Patient, COVID-19 diagnosis, POCT, recovered patients, total antibody, correlation, Quantitative, Critical, cross-reaction, COVID-19 patients, inactivated, specific antibodies, microneutralization, Concentration, COVID-19 cases, COVID-19 patient, reverse transcriptase, test results, Chain Reaction, intensity, Reactions, supplementary material, serum samples, Cutoff, quantitation, positive, total antibodies, cross-reactions, NAb titers, OD values, RBD-specific antibodies, vaccinees, serum sample, NAb titer, vaccinee, Seven, recovered patient, Result, defined, performed, significantly, healthy, indicated, clinically, evaluated, was determined, the receptor-binding domain, reveal, RBD-specific antibody, OD value, the antibody, 【제목키워드】 point-of-care, COVID-19 diagnosis, development, protective effect,