Osmolality

Normal values:

280 to 303 mOsm/kg

Note: mOsm/kg = milliosmoles per kilogram

What abnormal results mean:

Greater than normal levels may indicate:

• dehydration
• diabetes insipidus
• head trauma resulting in deficient ADH secretion
• hyperglycemia
• hypernatremia
• consumption of alcohol
• consumption of methanol
• consumption of ethylene glycol
• renal tubular necrosis
• severe pyelonephritis
• shock
• stroke resulting in deficient ADH secretion
• uremia

Lower than normal levels may indicate:

• excess fluid intake
• hyponatremia
• overhydration
• paraneoplastic syndromes associated with lung cancer
• syndrome of inappropriate ADH secretion

Additional conditions under which the test may be performed:

• complicated UTI (pyelonephritis)
• diabetic hyperglycemic hyperosmolar coma
• Hepatorenal syndrome
• interstitial nephritis