Crab meat and roe are highly nutritious delicacies in China. While extensive research has been conducted for allergens derived from crab-meat, data relevant to the allergenic potential of crab roe derived proteins, of which hemocyanin is a principal contender, are almost entirely absent. Using bioinformatics prediction and IgE-binding assays, the three principal immunodominant epitopes of hemocyanin were identified and then combined as a single recombinant fusion protein (rHc). This together with the full-length recombinant protein (Hc) were expressed in Escherichia coli and subsequently identified by SDS-PAGE and immunoblotting. Ninety-five percent of our patients were found to carry rHc-specific IgE antibodies by ELISA. Dot-blot inhibition, together with ELISA inhibition studies, showed that pre-incubation of patient sera with the recombinant epitope protein could inhibit26% to 63% (mean: 50%) of IgE binding to immobilized, full-length Hc and the dose-response curve represents as a sigmoid shape. The recombinant protein (rHc) represents a versatile biologic tool with which to diagnose and investigate therapies for E. sinensis allergy. Copyright © 2016 Elsevier Ltd. All rights reserved.