AVP and Central diabetes insipidus: Median copeptin levels were different in patients with central diabetes insipidus (3.39 pmol/L, IQR 1.99–3.90), salt overload (53.19 pmol/L, IQR 34.39–85.95) and dehydration-induced hypernatraemia (54.95 pmol/L, IQR 35.01–71.70) (P = 0.001).