The present invention relates to the method for treatment of tissue samples with proteolytic/histolytic additive collagenase or other similar protease prior to testing with an antigen capture immunoassay to identify cattle infected with Bovine Viral Diarrhea Virus (BVDV). The use of collagenase or other similar protease in antigen extraction step of the assay drastically increases accuracy of the assay, thus it allows for a more effective, reliable, quick, and cost effective way of identifying and thereby removing infected cattle and/or other animals from an otherwise uninfected herd.
