Letter to the Editor
Is copeptin a promising biomarker?
Contributed by Damien Gruson, Université de Louvain Member of the IFCC eNewsletter WG
gruson_damien@yahoo.fr
Emergency department (ED) overcrowding is common worldwide and may result in ambulance diversion and impaired ED responsiveness. In addition, ED overcrowding may also be associated with increased patient mortality. Patients attending the ED with chest pain indicating a possible acute coronary syndrome (ACS) are very common, and accurate diagnosis may require hours. Those patients may contribute to queuing at the ED and to elevated hospital costs because of an extensive length of stay and delay in their admission Copeptin, has been highlighted in different congresses in 2010 as an emergent biomarker in having a potential added value to rule out a suspected ACS in patients admitted to ED.
Copeptin, a 39-amino acid glycopeptide, is the C-terminal part of arginine-vasopressin pro-hormone, also termed antidiuretic hormone, has haemodynamic as well as osmoregulatory effects, and reflects the individual response to stress. It mirrors vasopressin levels, but is more stable in plasma and serum.
In 2009, Reichlin et al. (1) published a study investigating the value of incremental serum concentrtions of copeptin in rapidly ruling out acute myocardial infarction (AMI). The examination of copeptine concentration in 487 consecutive patients presenting to ED with symptoms suggestive of AMI, revealed that circulating levels below 14 pmol/l, in combination with troponin T concentrations below or equivalent to 0.01 mg/l, correctly ruled out AMI with a sensitivity of 98.8% and provided a negative predictive value of 99.7%.
This year, Keller et al. (2), confirmed these results by showing that the combined measurement of copeptin and Troponin T on admission improved the c-statistic from 0.84, for Troponin T alone, to 0.93 in establishing the diagnosis for AMI in 299 patients out of 1386 consecutively ED admitted patients.
Last, Enhörning et al. (3) have recently revealed another potential facet of copeptin utility. By reporting that increased circulating copeptin concentration predicts increased risk for diabetes mellitus independently of established clinical risk factors, including fasting glucose and insulin.
Copeptin testing is stimulating in 2010 both physicians and laboratorians. Nevertheless, as for every emerging and promising biomarker, careful validation of the analytical performances and reference values as well as the confirmation of its clinical value will be required.
References
- Reichlin T, Hochholzer W, Stelzig C, Laule K, Freidank H, Morgenthaler NG et al. Incremental value of copeptin for rapid rule out of acute myocardial infarction. J Am Coll Cardiol 2009;54:60-8.
- Keller T, Tzikas S, Zeller T, Czyz E, Lillpopp L, Ojeda FM et al. Copeptin improves early diagnosis of acute myocardial infarction. J Am Coll Cardiol 2010;55:2096-106.
- Enhörning S, Wang TJ, Nilsson PM, Almgren P, Hedblad B, Berglund G et al. Plasma copeptin and the risk of diabetes mellitus. Circulation 2010;121:2102-8.