To calculate the serum osmolality:
\[ \text{Osmolality} = 2 \times (\text{Na} + \text{K}) + \left(\frac{\text{BUN}}{2.8}\right) + \left(\frac{\text{Glucose}}{18}\right) \]
Where:
Serum osmolality is a laboratory test that measures the concentration of all chemical particles found in the fluids of your blood. These particles include electrolytes such as sodium, chloride, and bicarbonate, as well as sugars like glucose, and waste products like urea. The test is used to evaluate the balance of water to solute in your body, which is crucial for vital functions such as maintaining blood pressure, controlling body temperature, and ensuring proper function of the muscles and nerves. Abnormal serum osmolality levels can indicate a variety of conditions including dehydration, kidney disease, diabetes, or alcohol intoxication. The test is typically performed by drawing a blood sample from a vein in your arm.
Let's assume the following values:
Using the formula:
\[ \text{Osmolality} = 2 \times (140 + 4) + \left(\frac{20}{2.8}\right) + \left(\frac{90}{18}\right) = 2 \times 144 + 7.14 + 5 = 288 + 7.14 + 5 = 300.14 \]
The serum osmolality is 300.14 mOsm/kg.
Let's assume the following values:
Using the formula:
\[ \text{Osmolality} = 2 \times (135 + 5) + \left(\frac{15}{2.8}\right) + \left(\frac{100}{18}\right) = 2 \times 140 + 5.36 + 5.56 = 280 + 5.36 + 5.56 = 290.92 \]
The serum osmolality is 290.92 mOsm/kg.