AVP and Polyuria: Copeptin levels at T1 were significantly higher in those who developed polyuria compared to those who did not (79.0 [52.1-239.4] pmol/L vs. 17.9 [8.8–32.7] pmol/L, p = 0.013) (Table 3); in particular a copeptin value at T1 > 39.9 showed excellent ability (Se 100%, Sp 90.9%, AUC 0.932, p < 0.001) in identifying individuals at risk of developing polyuria in the first 2 days after surgery (Fig. 1A).