Allergenic properties of rat urine and pelt extracts

We studied the relative diagnostic efficacy of skin tests and RAST assays in laboratory animal allergy in 16 rat-sensitive animal workers with the use of epithelial extract and urinary antigens from three inbred rat strains. RAST inhibition was used to evaluate possible urinary antigen-strain specificity. The urinary antigens were more reliable skin test and RAST reagents than were epithelial extracts; data from urinary antigen testing correlated better with historical data. RAST inhibition did not detect strain specificity among the urinary antigens. Antigens in rat urine appear to be of better diagnostic value than do epithelial extracts.