Plasma copeptin in preterm infants: a highly sensitive marker of fetal and neonatal stress.

Context: Copeptin is a stable by-product of arginine-vasopressin synthesis and reflects its secretion by the pituitary.

Objective: The objective of the study was to investigate perinatal factors affecting copeptin concentrations in preterm infants at birth and at 3 d of life.

Design And Setting: This was a prospective cross-sectional study at two Swiss university hospitals.

Copeptin in the differential diagnosis of the polydipsia-polyuria syndrome--revisiting the direct and indirect water deprivation tests.

Background: The water deprivation test (WDT) with direct or indirect measurement of plasma arginine vasopressin (AVP) is the method of choice for the differential diagnosis of the polydipsia-polyuria syndrome. In theory, direct measurement of AVP is highly attractive but is hampered by technical difficulties.

Objective: The aim of the study was to evaluate the utility of copeptin, a surrogate of AVP secretion, in the diagnostic work-up of the polyuria-polydipsia syndrome and to compare its performance with the current diagnostic standard.

High copeptin concentrations in umbilical cord blood after vaginal delivery and birth acidosis.

Context: The pituitary-secreted nonapeptide arginine-vasopressin (AVP) is unstable and therefore unsuited for diagnostic use, but its secretion can be estimated by measuring copeptin, the C-terminal portion of the AVP precursor (pro-AVP).

Objective: Our objective was to investigate perinatal factors affecting copeptin concentrations in infants at birth and at 3 d of life.

Design And Setting: We conducted a prospective cross-sectional study at a tertiary university hospital.