This product is purified human IgE with kappa light chains produced in vitro from a hybridoma. Plasma IgE concentrations are low in normal patients. Elevated IgE levels are found in patients presenting severe allergic reactions and parasite infections. Original material was obtained from a healthy donor tested negative for HIV, HCV and hepatitis B by using US FDA-approved tests. Purity of human IgE is > 98% by SDS-PAGE analysis. There is no contamination by antibodies of other isotypes because of the cell line origin. Contaminants from foetal bovine serum were removed by Protein-L affinity chromatography. The material must be handled as potentially infectious as all human material. The product can be used as an IgE control in quantitative assays and for cell sensitization assays.