Normal Reference Ranges
Adult
50 - 1200 (fluid intake dependent) mOsm/kg H2O
Pediatric
Same as adult mOsm/kg H2O
Clinical Significance
Measures urine concentration. Critical in evaluating hyponatremia, hypernatremia, and polyuria.
Causes of High
- Dehydration
- SIADH
- Congestive Heart Failure
- Glycosuria
Causes of Low
- Diabetes insipidus (central or nephrogenic)
- Primary polydipsia
- Acute tubular necrosis