After excluding patients with PRL values > 250 μg/L, as they were already supposed to harbor a prolactinoma [5] the ROC analysis showed a fair accuracy for PRL in predicting the presence of a pituitary disease: the best cut-offs identified were >25 (1.6xULN) μg/L (Sensitivity [Se] 73.3%, Specificity [Sp] 80%, AUC 0.767, 95% CI 0.530–0.906, p = 0.003) and >44.2 (1.7xULN) μg/L (Se 69.6%, Sp 64.3%, AUC 0.697, 95% CI 0.567–0.794, p < 0.001) in men and women, respectively (Fig. 2A, B). This evidence concerns the gene PRL and pituitary gland disorder.