Urea-stimulated copeptin: a novel diagnostic approach in polyuria polydipsia syndrome
Authors' conclusion
Oral urea stimulates copeptin in healthy adults and patients with primary polydipsia, but not in patients with AVP-deficiency, establishing the first oral copeptin-based test in differentiating primary polydipsia from AVP-deficiency.
Study context
- Population
- Healthy adults (cross-over trial); patients with arginine vasopressin (AVP)-deficiency and patients with primary polydipsia (open-label pilot study, urea only)
- Participants
- 22 healthy adults
- Comparison
- Oral urea vs placebo
- Primary endpoint
- Maximum copeptin
- Follow-up
- Within 150 min
Methodological detailsdouble-blind, placebo-controlled, cross-over, open-label pilot study in patients
- Double-blind
- Placebo-controlled
- Cross-over
- Open-label pilot study in patients
Primary result
As reported in the abstract
Copeptin in healthy adults · maximum at 120 min
P < 0.001
- Baseline copeptin before urea, median [IQR] pmol/L
- 4.6 [3.0-5.7]
Further findings
- Copeptin after urea in patients (pilot study) — Primary polydipsia
- 7.4 (not stated 4.3–10.3) pmol/L
- Copeptin after urea in patients (pilot study) — Primary polydipsia: peak at 150 min
- 7.4 pmol/L [4.3, 10.3]
Copeptin after urea in patients (pilot study)
- AVP-deficiency: copeptin remained below detection limit throughout the test
Best copeptin cut-off to differentiate AVP-deficiency from primary polydipsia · 120 min
- Cut-off
- 3.5 pmol/L
- Sensitivity and specificity
- 93%
Original publication
Urea-stimulated copeptin: a novel diagnostic approach in polyuria polydipsia syndrome. Eur J Endocrinol. Published 1 April 2025. doi:10.
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