Osmolality Calculator
Calculate serum osmolality based on sodium, glucose, BUN, and ethanol values. Understand osmolar gaps and clinical implications of abnormal osmolality.
Step 1: Laboratory Values
Understanding Osmolality
Serum osmolality measures the concentration of dissolved particles in blood. Normal range is 275-295 mOsm/kg. High osmolality suggests dehydration, hyperglycemia, or intoxication, while low values may indicate overhydration.
Step 2: Calculation Options
About Osmolar Gap
The osmolar gap is the difference between measured and calculated osmolality. Normal gap is <10 mOsm/kg. Elevated gaps suggest the presence of unmeasured osmoles like methanol, ethylene glycol, or other toxins.
Osmolality Calculation Results
Calculated Serum Osmolality
Clinical Interpretation
| Osmolality Range | Clinical Significance | Possible Causes | Management Considerations |
|---|
Osmolar Gap Interpretation
Normal osmolar gap (<10 mOsm/kg). No evidence of unmeasured osmoles like methanol, ethylene glycol, or other toxins.
Component Contribution Analysis
Osmolality Formula
Standard Formula: 2 × [Na⁺] + [Glucose]/18 + [BUN]/2.8
With Ethanol: Standard + [Ethanol]/4.6
Simple Formula: 1.86 × [Na⁺] + [Glucose]/18 + [BUN]/2.8 + 9
Osmolar Gap = Measured Osmolality – Calculated Osmolality
Normal range: 275-295 mOsm/kg. Normal osmolar gap: <10 mOsm/kg.
Need Medical Consultation?
Connect with our certified medical professionals for expert interpretation of laboratory results, personalized health advice, and comprehensive medical consultations.
Get Medical Consultation