Application of the Positive/Negative Ratio Method of Analysis to Quantitate Antibody Responses to Infectious Bursal Disease Virus Using a Commercially Available ELISA

Abstract

An enzyme-linked immunosorbent assay (ELISA) test kit has been developed for infectious bursal disease virus (IBDV), and it is widely used for the detection and quantification of IBDV antibody. With results obtained using the commercial kit, a method of analysis was performed utilizing a positive/negative (P/N) ratio standard curve. A prediction equation was derived from this analysis by which the ELISA titer of a serum sample could be determined using one serum dilution. Values obtained using this method were compared with values obtained by the virus-neutralization equivalent method recommended by the kit manufacturer. The results were comparable in that the trends in titer were similar. The P/N ratio standard curve method is another way of determining titer using the IBDV ELISA test kit.