Copeptin (also known as CT-proAVP) is a 39-amino acid-long peptide deriving from a pre-pro-hormone consisting of vasopressin, neurophysin II and copeptin. Vasopressin (AVP), also known as the antidiuretic hormone (ADH), is involved in multiple cardiovascular and renal pathways and functions. However, vasopressin measurements are not commonly used in clinical routine, which is mainly due to the biochemical features of the molecule : its small size and very short half-life make vasopressin testing quite complicated and labor-intensive. On the other hand, copeptin can be immunologically tested with ease and therefore be used as a vasopressin surrogate.
The direct measurement of hypertonic saline-stimulated plasma copeptin had greater diagnostic accuracy than the water-deprivation test in patients with hypotonic polyuria. (Funded by the Swiss National Foundation and others; ClinicalTrials.gov number, NCT01940614 .) 1).
Adding copeptin to cardiac troponin (cTn) improved the sensitivity and negative predictive value for the diagnosis of non-ST elevation myocardial infarction (NSTEMI) compared to cTn alone. Thus, adding copeptin to cTn might help to screen NSTEMI early upon admission to the emergency department (ED) 2).
see Copeptin in stroke.