An increase in allergen-specific IgG4 (sIgG4), which serves as a blocking antibody, is associated with acquisition of immune tolerance after immunotherapy. In this study, we developed a rapid, sensitive, and homogeneous immunoassay based on the light-initiated chemiluminescent assay (LICA) technology for quantifying allergen sIgG4 in serum samples. Allergen sIgG4 was measured in vitro by incubating the sample with biotinylated allergens and chemiluminescent beads coated with anti-human IgG4 antibody, followed by the addition of streptavidin-coated sensitizer beads. Multiple tests were performed to optimize the working conditions of the LICA and evaluate its performance. We established the optimal concentration of biotinylated allergens (250 ng/mL), the optimal dilution range (1:8 for Gal d 1, Gal d 2 sIgG4 and 1:4 for Gal d 3, Gal d 4 sIgG4), and the optimal incubation time (20 min for Gal d 1, Gal d 2 sIgG4 and 40 min for Gal d 3, Gal d 4 sIgG4). The lower limit of quantification (LLOQ) was 0.261 ng/mL. The coefficient variation (CV) of the LICA was <10%. The assay was unaffected by general interfering substances at physiological concentrations. It exhibited excellent accuracy to detect allergen-sIgG4 in human serum. Additionally, we demonstrated that the levels of Gal d 1, Gal d 2, and Gal d 3-sIgG4 were significantly higher in the egg allergy group (p < .05), but no differences were found between the groups for Gal d 4-sIgG4. The LICA demonstrated satisfactory performance and can be used for quantifying allergen sIgG4 in clinical practice. Copyright © 2018 Elsevier B.V. All rights reserved.