Water Deprivation Test Results

Parameter

Normal

Complete ArginineVasopressin Deficiency

Partial ArginineVasopressin Deficiency

Complete ArginineVasopressin Resistance

Partial ArginineVasopressin Resistance

Primary Polydipsia

Uosm after dehydration (step 1)

Very high (> 700–800 mOsm/kg [> 700–800 mmol/kg])

Very low (less than plasma osmolality)

Low (≥ 300 mOsm/kg [≥ 300 mmol/kg])

Very low (less than plasma osmolality)

Very low (less than plasma osmolality)

High (500–600 mOsm/kg [500–600 mmol/kg])

Uosm increase after vasopressin (step 2)

Minimal (< 5%)

50 to > 100%

15–50%

< 50 mOsm/kg (<50 mmol/kg)

Up to 45%

No change

Uosm = urine osmolality.