Employers at laboratory animal facilities have begun to use selection criteria which proscribe employment of persons thought to be at increased risk of developing allergy to laboratory animals. Some of these criteria are: a personal history of allergy, chronic rhinitis, or asthma, positive direct skin tests, elevated serum immunoglobulin E, abnormal forced expiratory volume in 1 second, and a family history of allergy. The usefulness of these criteria were examined in preemployment screening when applied to job applicants who will be handling laboratory animals, by calculating the sensitivity, specificity, and positive predictive value (PPV) of each criterion. Results illustrated that the primary goal of the screening program must be determined before an evaluation can be made of the usefulness of potential screening criteria in meeting the goal, ie, to identify persons who are themselves at high risk (high PPV), to identify a large proportion of low-risk job applicants (specificity), or to screen out a large proportion of occupational disease (high sensitivity), because it is not possible to maximize these parameters simultaneously. Results indicate that, currently, the use of these screening criteria as determinants for hiring persons to work with laboratory animals is unwarranted.