Table 2.

SIADH Diagnostic Criteria

Essential Criteria
Effective serum osmolality <275 mOsm/kg
Urine osmolality >100 mOsm/kg with decreased effective osmolality
Evidence of clinical euvolaemia
Increased urine sodium concentration >30 mmol/l with normal salt and water intake
Normal adrenal, thyroid, pituitary or renal function
No recent use of diuretic drugs
Auxiliary Criteria
Serum uric acid <0.24 mmol/l (<4 mg/dl)
Serum urea <3.6 mmol/l (<21.6 mg/dl)
Failure to correct hyponatraemia after 0.9% saline administration
Fractional sodium excretion >0.5%
Fractional urea excretion >55%
Fractional uric acid excretion >12%
Correction of hyponatraemia through fluid restriction