Abstract: Rare-earth small molecule chelator  was used to prepare antibody markers of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2), and SARS-CoV-2 antigen was detected by time-resolved fluorescence immunochromatography. The experimental results show that the linear range of the method is 0.04—100 ng/mL,  the linear equation is y=0.007 2x+0.033 2, the correlation coefficient R²=0.999 5. The detection limit is 0.028 ng/mL. The intra-assay and inter-assay coefficients of variation are less than 6.72%,  and the recovery rate is  94.35%—103.00%. The method has the advantages such as good precision,  low detection time (less than 20 min),  low cost,  and simple operation.

Key words: time-resolved fluorescence immunochromatography,  , severe acute respiratory syndrome coronavirus 2 antigen,  , labeling antibodies with small molecule chelator,  , point-of-care testing