Why is My Osmolality Calculated Low?
Osmolality is a crucial measure in clinical settings, reflecting the number of osmoles of solute per kilogram of solvent. Understanding why your osmolality calculation might be low is essential for accurate diagnosis and treatment. This calculator and guide will help you understand and interpret osmolality results.
- Enter the serum osmolality, urine osmolality, and urine volume values.
- Click ‘Calculate’.
- Review the results and interpretation below the calculator.
The calculator uses the following formula to estimate the total solute excretion:
Total Solute Excretion (mOsm) = Urine Osmolality (mOsm/kg) × Urine Volume (mL) / 1000
The result is then compared to the serum osmolality to determine if it’s low, normal, or high.
| Condition | Serum Osmolality (mOsm/kg) | Urine Osmolality (mOsm/kg) |
|---|
- Always use fresh urine samples for accurate osmolality measurement.
- Consider other laboratory results and clinical context when interpreting osmolality.
- Consult with a healthcare professional for personalized advice.
What is the normal range for serum osmolality?
The normal range for serum osmolality is 275-295 mOsm/kg.
Learn more about osmolality from this PubMed article
Understand dehydration, a common cause of low osmolality, from Mayo Clinic