Affinity purified polyclonal antibody to Renibacterium salmoninarum made in goat and labeled with horseradish peroxidase. Isolated from a serum pool of goats immunized with heat killed whole cells of Renibacterium salmonarium. The antibody is highly specific for Renibacterium salmoninarum. Cross reactivity to other fish pathogens and normal fish flora has been minimized through extensive adsorption. Product is in lyophilized form. Each lot is tested to assure specificity and lot-to-lot consistency using an in-house ELISA assay.