Serum Osmolality
Calculate serum osmolality and osmolar gap.
Results
Visualization
How It Works
Serum osmolality is calculated as: (2 x Na) + (Glucose/18) + (BUN/2.8), with a normal range of 275-295 mOsm/kg. The osmolar gap (measured minus calculated) should be less than 10. An elevated gap suggests unmeasured osmoles such as methanol, ethylene glycol, isopropanol, or ethanol and requires urgent investigation.