Serum Osmolality Calculator
Calculate serum osmolality using sodium, glucose, and BUN values. Useful for assessing hydration status and electrolyte balance.
Published by:
isCalculator Editorial Team
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How to use this tool?
How to use the Serum Osmolality Calculator
- Enter Sodium (Na⁺) in mEq/L (e.g., 140).
- Enter Glucose in mg/dL (e.g., 100).
- Enter BUN (Blood Urea Nitrogen) in mg/dL (e.g., 20).
- Click Calculate.
Result: The calculator computes serum osmolality using the formula:
2 × Na⁺ + Glucose/18 + BUN/2.8 (units: mOsm/kg).
Interpretation:
- < 275 – Low (possible overhydration or hyponatremia).
- 275–295 – Normal.
- > 295 – High (possible dehydration or hypernatremia).
Note: All inputs must be in the specified units (mEq/L for sodium, mg/dL for glucose and BUN). Negative values are not allowed.
Previous Results
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Frequently Asked Questions
Serum osmolality measures the concentration of dissolved particles in the blood. It helps assess hydration status and electrolyte balance.
The formula is: 2 × Na⁺ + Glucose/18 + BUN/2.8, where Na⁺ is in mEq/L, glucose and BUN in mg/dL.
Normal serum osmolality ranges from 275 to 295 mOsm/kg. Values outside this range may indicate medical conditions.
