Application of the enzyme-linked immunosorbent assay for the detection of platelet antibodies in dogs.

An enzyme-linked immunosorbent assay (ELISA) was developed to detect serum antibodies reactive to canine platelets. The method used an anti-canine immunoglobulin G horseradish peroxidase conjugate, O-dianisidine, as a water-soluble chromagen, and pooled platelets as a temporary antibody support. The ELISA was compared with a conventional immunoinjury method measuring the accelerating effect of platelet factor 3 on coagulation. The ELISA was more sensitive in the detection of antiplatelet antibodies in canine patients with idiopathic thrombocytopenic purpura, autoimmune hemolytic anemia, and systemic lupus erythematosus. Serial dilution of rabbit anti-canine platelet serum revealed a positive correlation between the strength of the antiserum and the degree of color measured spectophotometrically, indicating that the absorbance value may be useful in estimating the amount of antibody present in the serum in indirect tests and on the platelets in direct tests.