Lack of specificity of current anti-digoxin antibodies, and preparation of a new, specific polyclonal antibody that recognizes the carbohydrate moiety of digoxin.

Current immunoassays for digoxin do not distinguish digoxin from its glycosidic metabolites. We have synthesized a novel digoxin/bovine serum albumin conjugate via reductive ozonolysis of the lactone ring such that the carbohydrate moiety of digoxin remains intact. Antibodies raised against this conjugate show minimal cross reactivity to digoxigenin, bisdigitoxide, monodigitoxide, digoxigenin, and digitoxin. With this antibody, digoxin can be measured in the presence of these metabolites.