What is the Osmolality Test?
The osmolality test measures the body’s ability to make urine, control urine and control water or fluid balance in blood. The most common cause for ordering the osmolality test is low blood sodium levels.

Normal Value Range

• Negative Pregnancy Adult: 275 to 295 mOsm/kg H2O or 275 to 295 nmol/kg
• Pregnancy Trimester One: 275 to 280 mOsm/kg H2O or 275 to 280 nmol/kg
• Pregnancy Trimester Two: 276 to 289 mOsm/kg H2O or 276 to 289 nmol/kg
• Pregnancy Trimester Three: 278 to 280 mOsm/kg H2O or 278 to 280 nmol/kg

Low osmolality can mean overconsumption of water, improper kidney function or urine production/concentration.

High osmolality could simply mean the body is dehydrated, but that is not the only possible cause. Diabetes, hyperglycemia and stroke can all cause abnormally high osmolality.

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