Osmolality, Serum
Serum osmolality measures how concentrated your blood is, reflecting the balance of water and dissolved particles like sodium, glucose, and urea. It's a marker of your body's fluid and electrolyte balance.
Osmolality helps your clinician understand hydration status and how your body regulates water, which is closely tied to sodium levels and hormones that control thirst and urine output.
A higher osmolality often reflects concentrated blood, as with dehydration, high blood sugar, or high sodium. It's interpreted alongside your electrolytes and hydration to find the cause.
A lower osmolality reflects more diluted blood, which can occur with excess water or low sodium, and is evaluated in context.
A typical range is roughly 275 to 295 mOsm/kg. Your clinician can interpret your value.
Sources
Educational context only, not medical advice or a diagnosis. Reference ranges vary by lab, age and sex; always discuss your results with a clinician.