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 a control.