Syndrome of inappropriate antidiuretic hormone secretion is diagnosed by all EXCEPT:

[Cl (Normal blood urea nitrogen) (2102-H 16lh) (769-70-CMDT-2009) (277-78-H17th)* Syndrome of inappropriate antidiuretic hormone secretion (SIADH)Clinical features* Hyponatremia* Decreased osmolality (< 280 mosm/kg) with inappropriately increased urine osmolalilty (> 150 mosm/kg)* Absence of cardiac, renal or liver disease* Normal thyroid and adrenal function* Urine sodium usually over 20 mEq/L.Other changes* Low blood urea nitrogen (BUN) (< 10 mg/dL)* Hypouricemia (< 4 mg/dL)* A high BUN suggests a volume state, which excludes a diagnosis of SIADH.