Validation of a domestic ELISA and determination of the best cut off point for seroepidemiological study of enzootic bovine leukosis

    The aim of this study was to compare the validation of a Domestic Indirect-ELISA with a Commercial Indirect-ELISA  in order to find the optimum cut off value for detection of antibodies to Bovine Leukemia Virus (BLV). BLV proteins harvested easily as described by OIE and used in DI-ELISA. A domestic ELISA was adapted by checker board methods. 460 sera from different herds were applied in the commercial ELISA as a reference test and then compared with the domestic ELISA. All the negative control sera except one (E05 serum) were chosen by commercial ELISA.  Statistical analysis of negative sera showed that consideration of  a cut off value, from 0.26 to 0.30  will provide acceptable  relative specifity, relative sensitivity and can reducing the risk of false positive results for Domestic Indirect ELISA. The best relative sensitivity (86%) and specifity (88%) was yielded in 0.27 optical density (OD).
As calculated, frequency of seropositive animals was 8% and 10% by domestic and commercial ELISA respectively.