Validation of five commercially available ELISAs for the detection of antibodies against infectious bursal disease virus (serotype 1)

In this study, the results are reported from a validation study of five com mercially available enzyme-linked immunosorbent assays (ELISAs) for the det ection of antibodies against infectious bursal disease virus ( IBDV), serot ype 1. The specificity of the ELISAs varied from 63.8 to 100%. All ELISAs r eached a sensitivity of 100% on sera between 14 and 21 days post-vaccinatio n (d.p.v.) with two classical vaccines and a Delaware variant-E virus. Over all, most birds became positive between 8 and 11 d.p.v. As expected, the EL ISA with the lowest specificity showed the highest sensitivity at 5 d.p.v. When the decrease in maternally derived antibodies against IBDV was measure d, a highly significant correlation (P<0.001) was found for all ELISAs and the virus neutralization test (VNT). R-2 varied from 0.44 to 0.76, whereas the slope varied from 0.33 to 0.57. This indicates that there is a certain correlation between VNT and ELISA titres, but that the correlation differs from ELISA to ELISA. For all ELISAs, no significant (P<0.05) differences in level of antibodies were detected between antibody titres in breeder serum , egg yolk and progeny at 1 and 4 days of age. This validation of five comm ercially available ELISAs for the detection of antibodies against IBDV (ser otype 1) shows that there are significant differences in their performance. Therefore, choosing an ELISA or interpreting ELISA results without knowing the technical performance should be avoided.