Table 1.

Diagnostic criteria for central diabetes insipidus

Clinical feature	Diagnostic finding
Increased urine volume	Urine output > 3–4 L/day or > 2.5–3.0 mL/kg/h
Hypernatremia	Serum sodium concentration > 145 mmol/L
Normal or increased serum osmolality	Serum osmolality > 305 mmol/kg
Inappropriately dilute urine	Urine osmolality < 200 mmol/kg or specific gravity < 1.005a

^aWhilst waiting for laboratory tests, a simple, but not 100% reliable, bedside test of urine specific gravity (SG) may be useful. In the presence of high urine output and high serum sodium, urine SG < 1.005 is suggestive of diabetes insipidus