Validation of Elisa for Testing of Antirabies Antibodies

Indirect ELISA was evaluated for quantifying specific antirabies antibodies. A total of 4,946 samples of sixty equines were monitored by indirect ELISA at an interval of two weeks for a period of five years. When seven equines of the above sixty were compared for VNT and indirect ELISA during their primary phase of immunization, a good correlation was observed (r = 1.0). Based on this, the equines were segregated into 'Low' responders, 'Medium' responders and 'High' responders. This segregation of equines based on their antibody titres proved to be very useful for initiating corrective remedial measures. On comparison of 14 Plasma samples, 31 Purified bulk sera samples and 17 Batch samples for VNT and indirect ELISA, a good correlation (r = 0.82, 0.923 & 0.874 respectively) was observed. The sensitivity values observed were 100 %, 100%, 90.7 % & 90.9% and specificity values were 100%, 100%, 94.7% & 100% for Equine sera, Plasma, Purified bulk sera and Batch samples respectively. The Cohen's Kappa index also reflected a good agreement between the indirect ELISA test and the VNT test for Equine sera samples.