Blood Serum Osmolality Calculator

Calculate Blood Serum Osmolality

Enter value in mEq/L (milliequivalents per liter).
Enter value in mg/dL (milligrams per deciliter).
Enter value in mg/dL (milligrams per deciliter).

Quickly determine blood serum osmolality, a vital metric for evaluating fluid and electrolyte balance. This free online calculator helps medical professionals and students assess conditions like dehydration, hypernatremia, and kidney function based on key lab values.

Formula:

The standard formula used for calculating blood serum osmolality is:

Osmolality (mOsm/kg) = (2 * Na) + (Glucose / 18) + (BUN / 2.8)

Where:

  • Na: Serum Sodium concentration (mEq/L)
  • Glucose: Blood Glucose concentration (mg/dL)
  • BUN: Blood Urea Nitrogen concentration (mg/dL)

Note: These divisions (18 for glucose, 2.8 for BUN) convert mg/dL to mmol/L for calculation.

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