Antiheparin antibodies: their preparation and use in a heparin immunoassay.

Antibodies that recognize unmodified heparin bound to positively charged macromolecules have been obtained by immunizing rabbits with a methylated bovine serum albumin-heparin precipitate. These antibodies have been used to develop an immunoassay that can quantitate heparin at a concentration of 5 ng/ml in buffer solutions, and at a concentration of 25 ng/ml in plasma without pretreatment of the sample. The specificity of the antibodies is such that they do not recognize other glycosaminoglycans and are able to distinguish among different commercial heparin samples that are otherwise indistinguishable by specific anticoagulant activity or molecular weight distribution.