What is the IVIG Dose Calculator?
Intravenous immunoglobulin (IVIG) is dosed by body weight, typically expressed in grams per kilogram (g/kg). This calculator converts a prescribed dose per kilogram into the total grams of IVIG required for a patient, and then translates that into the actual infusion volume in milliliters based on the concentration of the IVIG product being used. It is intended as a clinical decision-support aid; always verify against local protocols, product labeling, and prescriber orders.
How to use it
Enter three values: the patient's weight in kilograms, the prescribed dose in grams per kilogram, and the concentration of the IVIG product in milligrams per milliliter. Common regimens include 0.4 g/kg daily for several days (immune deficiency) or up to 2 g/kg for immunomodulation. Products are commonly supplied at concentrations of 50, 100, or 200 mg/mL. The calculator returns the total dose in grams and the corresponding volume to administer.
The formula explained
The total dose is simply the dose per kilogram multiplied by the weight: $$\text{Dose (g)} = D \text{ (g/kg)} \times W \text{ (kg)}$$. To find the volume, the dose in grams is converted to milligrams (\(\times 1000\)) and divided by the concentration in mg/mL: $$\text{Volume (mL)} = \frac{\text{Dose (g)} \times 1000}{C \text{ (mg/mL)}}$$. The factor of 1000 reconciles grams with the milligram-based concentration.
Worked example
For an 80 kg patient prescribed 0.4 g/kg using a 100 mg/mL product: Total dose = \(0.4 \times 80 = 32\) g. Volume = \(\dfrac{32 \times 1000}{100} = 320\) mL.
FAQ
Should I use actual or ideal body weight? In obese patients many protocols use an adjusted or ideal body weight to avoid overdosing; follow your institutional guideline.
What concentration should I enter? Use the concentration printed on the specific product vial — it varies by brand and formulation.
Is rounding needed? Vials come in fixed sizes, so the final dispensed amount is usually rounded to the nearest vial; treat this output as the calculated target.
