Winzeler B, Cesana-Nigro N, Refardt J, et al. - Via a prospective diagnostic study that recruited a development cohort from University Hospital Basel, Basel, Switzerland, and a validation cohort from five centres in Basel, Aarau, Luzern, Bern, and St Gallen, Switzerland, and the University Hospital Würzburg, Würzburg, Germany, consisting of 52 patients aged 18 years or older, who were freshly referred with polyuria (> 50 mL/kg bodyweight per day) or had a known diagnosis of central diabetes insipidus or primary polydipsia, researchers determined an alternative, simple, and safe test, arginine-stimulated copeptin measurements, in the differential diagnosis of diabetes insipidus. Arginine-stimulated copeptin measurements was found to be an innovative test for diabetes insipidus with high diagnostic exactitude, and could be a simplified, novel, and safe diagnostic strategy to diabetes insipidus in clinical practice.