Background: Hypo- and hypernatremia are common in hospitalized patients. The differential
diagnosis of dysnatremia is challenging.
Osmotically inadequate secretion of antidiuretic hormone (ADH) is the predominant mechanism
in most dysnatremic disorders. ADH measurement is cumbersome. It is derived from a larger
precursor peptide along with copeptin, which is a more stable peptide directly mirroring the
production of ADH.
Objective: To evaluate the additional value of copeptin to improve a currently used algorithm
in the differential diagnosis of (A) severe hypoosmolar hypo- and (B) severe hypernatremia.
Design: Prospective observational study.