RESUMO
<p><b>OBJECTIVE</b>To prepare a time-resolved fluoroimmunoassay (TRFIA) kit for clinical detection of IgM antibodies to hepatitis B core antigen (HBc).</p><p><b>METHODS</b>Immunocapture method was used to develop the TRFIA kit for detection of the anti-HBc IgM antibodies, and the precision, cross-reactivity and sensitivity of the kit were tested with the clinical serum samples.</p><p><b>RESULTS</b>The intra- and inter-assay coefficients of variation of the TRFIA kit were 4.8%-7.2% and 7.5%-8.6%, respectively, and no cross-reactivity with anti-HBs, anti-HBc-IgG or anti-HBe was found. Comparison of the results of the TRFIA kit and enzyme-linked immunosorbent assay (ELISA) demonstrated greater sensitivity of the kit than ELISA in detecting the anti-HBc IgM antibodies in 584 serum samples. According to the detection results in 300 serum samples from healthy donors, the cutoff value of the TRFIA kit was 4.5 times of the fluorescence value of the negative control.</p><p><b>CONCLUSION</b>This TRFIA kit for detecting anti-HBc IgM antibodies meets the demand for clinical application and can replace the ELISA kits.</p>