Time-resolved fluorescence immunoassay（TRFIA） is a non-isotopic immunoassay technique, which uses lanthanide elements to label antigens or antibodies. According to the luminescence characteristics of lanthanide chelates, time-resolved technology is used to measure fluorescence, and the two parameters of wavelength and time are simultaneously detected for signal resolution. The interference of non-specific fluorescence is effectively eliminated, and the analysis sensitivity is greatly improved.