Elimination of cross-reactivity to some component of erythrocytes in an antiserum to parathyroid hormone by absorption with fixed erythrocytes

Cross-reactivity to some component of rat erythrocytes with an antiserum to parathyroid hormone (anti-PTH) was detected in fixed demineralized sections of bone using the peroxidase-antiperoxidase method. The cross-reactivity was eliminated by the preabsorption of anti-PTH with fixed, washed rat erythrocytes. This technique provides an easy and rapid method with which to eliminate cross-reactivity to erythrocytes whenever such a situation is encountered in immunohistochemical procedures.