Copeptin is a new diagnostic biomarker for diabetes insipidus

Differential diagnosis of diabetes insipidus is challenging. The water deprivation test is the current gold standard, but the test is cumbersome, and the diagnostic performance is poor. Copeptin, which is a split product of the vasopressin pre-propeptide, appears to be a robust biomarker in the circulation and a promising tool for the diagnosis of patients with polyuria and polydipsia, especially when measured in conjunction with intravenous infusion of arginine, as summarised in this review.