Abstract:Abstract: Objective:To establish an immunomagnetic bead (IMB) assay for the detection of human serum specific IgG antibody to the enolase of Candida albicans, and evaluate its value in the diagnosis of candidemia. Methods:The immunomagnetic beads conjugated with recombinant enolase of Candida albicans were served as the solid phase, and HRP labeled goat anti human IgG as the second antibody. Then, the reaction conditions were optimized, and the accuracy and specificity of the established IMB assay evaluated. Serum samples from the patients with invasive candidemia(n=113), Candidaspp. colonization(n=50), bacteremia (n=30) and the health controls (n=100) were collected, and the IgG antibody to enolase in these samples was determined by the IMB assay and ELISA, respectively, and their results compared. Results:The intra- and inter-assay coefficients of variation of the IMB assay were 8.2% and 14.2%, respectively. There was 91.6% of antibody to enolase in sera blocked by recombinant enolase. With the absorbance value of 0.29 as the cut off, the sensitivity, specificity, positive predictive value and negative predictive value for diagnosing candidemia were 80.5%, 92.3%, 90.1% and 84.5%, respectively. There was no significant difference in diagnostic performance between the IMB assay and ELISA. However, the entire duration in the IMB assay (1 hour at room temperature) was shorter than that in ELISA (2.5 h at 37 ℃). Conclusion:The established IMB assay is simple, rapid and reliable for the detection of IgG antibody to Candida albicans enolase, which has the potential application value in the research of invasive candidiasis.