IgE is the least abundant immunoglobulin in plasma, found at a concentration of less that 0.6 micrograms/ml of normal plasma. Elevated IgE levels are found in patients experiencing severe allergic reactions and parasitic infections. In a myeloma condition, IgE is produced by a single clone of plasma cells. The structure of myeloma IgE, however, is normal, and the immunoglobulin purified from a myeloma source is a useful protein for studying immunoglobulin behavior. The affinity purified IgE reacted only with anti IgE and not with anti IgG, IgA, IgM or IgD by immunodiffusion and IEP techniques. Prepared from myeloma plasma shown to be non reactive for HbsAG, anti-HCV, anti-HBc, and negative for anti-HIV 1 & 2 by FDA approved tests.