Copeptin (also known as copeptin proAVP or copeptin AVP) and arginine vasopressin (AVP) are derived from the same precursor peptide. Both are affected by osmolar status and increase in response to water deprivation. AVP is the major physiologic determinant of urinary free water excretion or retention. Copeptin proAVP is an improved replacement for AVP testing that is useful as part of differential diagnosis of patients with water balance disorders, including diabetes insipidus (DI) and primary polydipsia, in conjunction with osmolality and hydration status.
Joshua Bornhorst, Ph.D., gives an overview of the new copeptin test available through Mayo Clinic Laboratories. He discusses when this testing should be ordered, how this testing improves upon previous testing approaches, and what clinical action can be taken due to the results of this testing.
When to Order
- The investigation of the differential diagnosis of patients with water balance disorders, including diabetes insipidus (DI), in conjunction with osmolality and hydration status.
- May aid in the evaluation of cardiovascular disease in conjunction with other cardiac markers.
- Patient Preparation: For water-deprived testing have the patient fast and thirst for at least 8 hours (no liquids, including water, are allowed).
- Specimen Type: Plasma
- Collection Container/Tube: Lavender top (EDTA)
- Submission Container/Tube: Plastic screw-top aliquot tube
- Specimen Volume: 0.5 mL
- Collection Instructions: Spin down and remove plasma. Do not submit in original tube.
Day(s) and Time(s) Test Performed
- Monday through Friday; 6 a.m.–12 a.m., Saturday; 6 a.m.–5 p.m.
- Same day/1 day