Allowable Blood Loss Calculator

Formula

To calculate the allowable blood loss:

\[ \text{ABL} = \frac{\text{Patient Weight} \times (\text{Initial Hct} - \text{Final Hct}) \times 70}{\text{Initial Hct}} \]

Where:

\(\text{ABL}\) is the Allowable Blood Loss (mL)
\(\text{Patient Weight}\) is the weight of the patient (kg)
\(\text{Initial Hct}\) is the initial hematocrit (%)
\(\text{Final Hct}\) is the final hematocrit (%) after which a transfusion is considered

What is Allowable Blood Loss?

Allowable blood loss is the volume of blood that a patient can safely lose during surgery or a medical procedure without the need for a blood transfusion. It is based on the patient’s weight and hematocrit levels. Hematocrit is the percentage of red blood cells in the blood, and it is a key factor in determining the oxygen-carrying capacity of the blood. The ABL is an important consideration in preoperative planning and patient safety.

Example Calculation 1

Let's assume the following values:

Patient Weight = 70 kg
Initial Hematocrit = 45%
Final Hematocrit = 30%

Using the formula:

\[ \text{ABL} = \frac{70 \times (45 - 30) \times 70}{45} = \frac{70 \times 15 \times 70}{45} \approx 1633.33 \, \text{mL} \]

The Allowable Blood Loss is approximately 1633.33 mL.

Example Calculation 2

Let's assume the following values:

Patient Weight = 60 kg
Initial Hematocrit = 40%
Final Hematocrit = 25%