Serum Osmolality

Blood Osmolality Test, Osmolality Test

Why It Is Done

Serum osmolality is measured to:

• Check the balance between the water and the chemicals dissolved in blood.
• Find out if severe dehydration or overhydration is present.
• Check to see if the hypothalamus is producing enough antidiuretic hormone (ADH).
• Find the cause of seizures or coma. In severe cases, an imbalance between water and electrolytes in the body can cause seizures or coma.
• Find out if a person has swallowed certain poisons, such as rubbing alcohol (isopropanol), wood alcohol (methanol), or antifreeze (ethylene glycol). Serum osmolality can also help find out how much of these poisons are present in the blood.

Go to previous section	Go to top of page	Go to next section
Author:	Maria G. Essig, MS, ELS Ralph Poore	Last Updated: January 29, 2008
Medical Review:	Anne C. Poinier, MD - Internal Medicine Caroline S. Rhoads, MD - Internal Medicine David C.W. Lau, MD, PhD, FRCPC - Endocrinology & Metabolism
© 1995-2008 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.This information does not replace the advice of a doctor. Healthwise disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. How this information was developed to help you make better health decisions.