Equitech-Bio's purified immunoglobulin (Ig) preparations are isolated from pooled normal serum by a proprietary fractionation method. The immunoglobulin preparations are supplied as a liquid. Purity levels are >97% IgG as analyzed by SDS-Page. These preparations are especially useful as a co-precipitant in RIA methods employing polyethylene glycol or ammonium sulfate precipitation steps, or as a protein stabilizer blocker in a number of immunoassays. These preparations are also useful as IgG control solutions for biochemical analytical tests. Immunoglobulin preparations are provided at pH 7.2