Serum Osmolality Calculator

Calculate serum osmolality based on sodium, glucose, and urea nitrogen levels in blood plasma

Input Parameters

Calculation Results

Calculation Formula

Serum Osmolality = 2 × [Sodium] + [Glucose]/18 + [Urea Nitrogen]/2.8

Where:
- Sodium is in mEq/L
- Glucose is in mg/dL
- Urea Nitrogen is in mg/dL
- The result is in mOsm/kg

Interpretation

  • Normal range: 280-295 mOsm/kg
  • High osmolality (>295 mOsm/kg) may indicate:
  • - Diabetes mellitus
  • - Dehydration
  • - Ethanol consumption
  • Low osmolality (<280 mOsm/kg) may indicate:
  • - Hypothyroidism
  • - Adrenal insufficiency
  • - Myxedema

Serum Osmolality Calculator Calculator Usage Guide

Learn how to use the Serum Osmolality Calculator calculator and its working principles

How to Use This Calculator

  1. Enter your sodium level in mEq/L (milliequivalents per liter)
  2. Enter your glucose level in mg/dL (milligrams per deciliter)
  3. Enter your urea nitrogen level in mg/dL (milligrams per deciliter)
  4. Click the "Calculate" button to compute your serum osmolality
  5. Review the result and interpretation provided

Understanding Serum Osmolality

Serum osmolality is a measure of the total solute concentration in blood plasma. It helps in diagnosing and monitoring various conditions including dehydration, diabetes, and kidney disorders.

The formula used in this calculator is based on the most common method for estimating serum osmolality:

Serum Osmolality = 2 × [Sodium] + [Glucose]/18 + [Urea Nitrogen]/2.8

Where:
- Sodium is in mEq/L
- Glucose is in mg/dL
- Urea Nitrogen is in mg/dL
- The result is in mOsm/kg (milliosmoles per kilogram)

Normal Range and Clinical Significance

The normal range for serum osmolality is typically 280-295 mOsm/kg. Values outside this range may indicate various medical conditions:

  • High Osmolality (>295 mOsm/kg): May suggest diabetes mellitus, dehydration, alcohol consumption, or other conditions that increase solute concentration in the blood.
  • Low Osmolality (<280 mOsm/kg): May indicate hypothyroidism, adrenal insufficiency, myxedema, or other conditions that decrease solute concentration.

Important Notes

This calculator provides an estimate of serum osmolality based on laboratory values. It should not be used for diagnostic purposes without consulting a healthcare professional. Always follow up with appropriate medical evaluation for any abnormal results.