What is a copeptin test for?
What is a copeptin test for?
A blood test for copeptin, a precursor of antidiuretic hormone (ADH, vasopressin), differentiates between “harmless” polydipsia-polyuria and diabetes insipidus more quickly and accurately than a traditional water-deprivation test, researchers report.
What does elevated copeptin mean?
Increased Levels of Copeptin, a Surrogate Marker of Arginine Vasopressin, Are Associated with an Increased Risk of Chronic Kidney Disease in a General Population.
What is copeptin level?
Normal values of copeptin in healthy volunteers range between 1.70–11.25 pmol/L (6,9,10). Copeptin also shows minimal intra-individual variations (11).
What does low copeptin mean?
Copeptin levels reliably identified patients with central diabetes insipidus. Low copeptin levels have already been shown to indicate central diabetes insipidus in ambulatory patients presenting with polyuria polydipsia syndrome [29] and in patients after pituitary surgery [30].
Is copeptin the same as ADH?
ADH and copeptin are released in the body in a 1:1 ratio as 2 parts of the arginine vasopressin precursor. Copeptin is more stable and can be measured by immunoassay. It can therefore be reliably used as a surrogate marker for ADH.
What is serum copeptin?
Abstract. Copeptin is secreted in an equimolar amount to arginine vasopressin (AVP) but can easily be measured in plasma or serum with a sandwich immunoassay. The main stimuli for copeptin are similar to AVP, that is an increase in osmolality and a decrease in arterial blood volume and pressure.
What is plasma copeptin?
Copeptin has been proposed as a more stable, potentially superior, surrogate marker of AVP in the assessment of water balance disorders. Unlike AVP, copeptin is stable in plasma. Both copeptin and AVP are responsive to osmotic stimuli and increase in response to water deprivation.
How is copeptin used to diagnose diabetes?
When the prespecified morning copeptin cutoff level of less than 2.6 pmol per liter after overnight water deprivation was used to identify patients with complete central diabetes insipidus, the diagnostic accuracy was 78.4% (95% CI, 70.6 to 84.9).
How long does it take to do a copeptin assay?
Scheme of assay for the measurement of copeptin is shown in Figure 2. The assay requires minimal serum or plasma volume and the overall time for completing the analysis is between 20 and 30 minutes (13). Based on these facts, copeptin is suitable for routine measurements as an alternative to AVP (6).
How long is copeptin stable in EDTA plasma?
Unlike AVP, copeptin is stable in EDTA plasma for up to 14 days at room temperature, while in citrate and heparin plasma copeptin is stable for 7 days (19). Its detection doesn’t require extraction or other complex preanalytical steps (13).
Can a direct water deprivation test detect copeptin?
However, it is technically cumbersome to administer, and the results are often inaccurate. The current study compared the indirect water-deprivation test with direct detection of plasma copeptin, a precursor-derived surrogate of arginine vasopressin.
