desmopressin stimulation test

Indications

• suspected diabetes insipidus (DI)
• when urine does NOT concentrate in water deprivation test

Procedure

• measure urine osmolality
• inject 5 units (1 ug) of subcutaneous (SC) or intravenous (IV) desopressin
• measure urine osmolality every 30 minutes for 2 hours after administrationof desopressin

Interpretation

• an increased urine osmolality indicates central DI (urine osmolality more than doubles with central DI)
• a lack of response indicates nephrogenic DI
• patients with primary polydipsia may show response similar to nephrogenic DI due to washout of the medullary concentration gradient

More general terms

• provocative clinical test