The Dutch diagnostic model for laboratory animal allergen sensitization was generalizable in Canadian apprentices

To assess the transportability of an existing diagnostic questionnaire model for the sensitization to laboratory animal (LA) allergens.

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).

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 P<0.001). The other methods yielded models with good calibration (P>0.10) 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).

Once updated, the diagnostic model is valid and can be applied with reasonable performance in an animal health apprentice setting.