OBJECTIVE: To assess the transportability of an existing diagnostic questionnaire model for the sensitization to laboratory animal (LA) allergens. STUDY DESIGN AND SETTING: The model was externally validated in 414 Canadian animal health apprentices. Several approaches were used: (1) no adjustment; (2) recalibration of the intercept of the model; (3) re-estimation of the intercept and the regression coefficients of predictors; and (4) model revision, by excluding the existing predictor(s) and/or including new predictor(s). The bootstrapping procedure was done following the third and fourth methods. The calibration was assessed graphically and with the Hosmer-Lemeshow (HL) test. Discriminative properties were determined by the area under the receiver operating characteristic curve (ROC area). RESULTS: When applied without adjustment, the model's discriminative ability was adequate (ROC area was 0.74 vs. the original ROC area of 0.76); the calibration was poor (HL test P0.10) and reasonable discrimination (ROC area ranged between 0.73 and 0.75). The refitted and revised model showed a good internal validity (correction factor from the bootstrapping procedure was more than 0.90). CONCLUSION: Once updated, the diagnostic model is valid and can be applied with reasonable performance in an animal health apprentice setting.