Copeptin – CT-proAVP (diabetes insipidus)

General Information

Arginine-vasopressin (AVP) and copeptin are derived from the same precursor peptide, preprovasopressin, along with neurophysin II and vasopressin. Copeptin is released together with vasopressin from the magno and parvocellular neurons of the hypothalamus during the conversion of the precursor protein.

Copeptin is much more stable in plasma than arginine-vasopressin, so it is used to detect water-electrolyte imbalance. Both copeptin and arginine-vasopressin are sensitive to osmotic stimuli and their concentrations increase in response to body water deficit.

In diabetes insipidus, the ability to concentrate urine in response to osmotic stimuli is impaired.

The main cause of central diabetes insipidus is a decrease in arginine-vasopressin production. Nephrogenic diabetes insipidus is caused by decreased renal response to arginine-vasopressin.

Determination of plasma copeptin is essential for the diagnostics of arginine-vasopressin-related disorders. Determination of copeptin is also provided in case of violation of antidiuretic hormone secretion.

Copeptin is also a marker of acute hemodynamic stress. It is important to diagnose cardiac disorders such as acute coronary syndrome, stable coronary artery disease (stable angina), congestive heart failure, and acute ischemic stroke.

Biomarker of polyuria-polydipsia

Because copeptin corresponds to and reflects the amount of vasopressin in the circulation, it is a biomarker for conditions such as polydipsia-polyuria (increased thirst, frequent urination) and hyponatremia (decreased sodium concentration in the blood). These symptoms are clinical manifestations of central diabetes insipidus, nephrogenic diabetes insipidus and primary polydipsia.

Material for examination: Venous blood

Research method: Immunofluorescence study