[Plasma copeptin--a multi-purpose diagnostic tool for clinicians?].

Measurement of antidiuretic hormone (ADH) is utilized in the diagnosis of hyponatremia and polyuria. However, determination of ADH is slow, and results may be unreliable. Copeptin is a glycopeptide of 39 amino acid residues that is cleaved from a precursor of ADH and secreted to the circulation in an equimolar manner with ADH. Determination of the copeptin level is quick and reliable, and improves the diagnostics of osmotic disorders. Copeptin seems to be a promising diagnostic tool also in acute coronary syndrome and may have prognostic significance in cardiac insufficiency, stroke or septicaemia, too.