Initial evaluation of low sodium in adults*

BUN: blood urea nitrogen; TURP: transurethral resection of the prostate; SIADH: syndrome of inappropriate antidiuretic hormone secretion; TSH: thyroid-stimulating hormone.

* The normal serum sodium is 135 to 146 mEq/L (mmol/L). Interpretation of a specific abnormal result should be based upon the reference range reported for that result.

¶ Life-saving interventions should not be delayed while awaiting the results of diagnostic testing.

Δ Add 2 mEq/L to the serum sodium for every 100 mg/dL of serum glucose above the normal value.