A fluorescence enzyme immunoassay (ChymoFAST test) for the quantitation of chymopapain-specific IgE antibody concentration in human serum is described. The IgE antibody is recognized as the major immunologic mediator for anaphylactic reactions. Serum chymopapain-specific IgE levels serve as an objective screening method for identifying patients most likely to tolerate chymopapain, thereby minimizing associated risks. Preoperative sera obtained from 11,658 chemonucleolysis candidates were tested, of which 0.94% (110/11,658) were found to be positive. Good predictive values for both positive and negative findings are evident based on 4776 postmarketing surveillances obtained from the surgeons.