Copeptin is produced at a 1:1 ratio with vasopressin (Figure 1) and is more stable in plasma samples, and therefore, it is used as a surrogate for vasopressin levels.15,26, –28 Multiple studies have found an association between elevated blood copeptin levels, high-fat diet, metabolic syndrome, cardiovascular disease, diabetes mellitus, and CKD.29, , –32 Vasopressin is made in the hypothalamus and released by the posterior pituitary. Here, AVP is linked to diabetes mellitus.