SIADH Diagnostic Criteria (Bartter-Schwartz)

Essential Criteria (Bartter-Schwartz)0 / 6

Supplemental criteria for SIADH include a low serum uric acid ( < 4 mg/dL), low BUN, and fractional excretion of sodium > 1%. Note: Clinical euvolemia is essential; if the patient is edematous, consider CHF or Nephrosis.

Guidelines & Evidence

Verified

Last Review: 2026

When to Use

Differential diagnosis of hypotonic hyponatremia (Na < 135, Posm < 275).

Screening for inappropriate ADH secretion in euvolemic patients.

Evaluating suspected drug-induced (SSRIs, carbamazepine) or paraneoplastic SIADH.

Clinical Pearls

Supplemental Features

Parameter	Characteristic SIADH Finding
Serum Uric Acid	< 4 mg/dL
BUN	Low (< 10 mg/dL)
Fractional Excretion of Na	> 1%
FE of Urea	> 55%

Differential Trap

Cerebral Salt Wasting (CSW) is the main mimic of SIADH in neurosurgical patients. Unlike SIADH, CSW patients are HYPOVOLEMIC and have an appropriately high urine sodium due to primary sodium wasting. CSW is treated with salt and fluid replacement, whereas SIADH is treated with fluid restriction.

Last Comprehensive Review: 2026

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SIADH Diagnostic Criteria (Bartter-Schwartz)

When to Use

When to Use

How it Works

The Bartter-Schwartz Criteria

Clinical Pearls

Supplemental Features

Differential Trap

The Evidence

Primary Source

The syndrome of inappropriate secretion of antidiuretic hormone.

Recent Journal Updates

SIADH Diagnostic Criteria (Bartter-Schwartz)

When to Use

When to Use

How it Works

The Bartter-Schwartz Criteria

Clinical Pearls

Supplemental Features

Differential Trap

The Evidence

Primary Source

The syndrome of inappropriate secretion of antidiuretic hormone.

Recent Journal Updates