IVIG Dose Calculator
Calculate IVIG dosing based on patient weight and prescribed dose parameters.
Patient Parameters
What This Calculator Does
This IVIG dose calculator determines the total immunoglobulin dose and infusion volume required for a patient based on their body weight and the prescribed dose in grams per kilogram (g/kg). It is designed for healthcare professionals who need to quickly verify dosing calculations for intravenous immunoglobulin therapy.
How the Calculation Works
The calculator uses a straightforward formula:
Total Dose (g) = Patient Weight (kg) × Prescribed Dose (g/kg)
For example, a patient weighing 70 kg receiving a standard replacement dose of 0.4 g/kg would require a total dose of 28 grams of IVIG.
The calculator also estimates the infusion volume based on the concentration of the IVIG product. Most IVIG preparations are available as a 5% or 10% solution, where:
- 5% solution: 1 gram of IVIG per 20 mL of fluid
- 10% solution: 1 gram of IVIG per 10 mL of fluid
The infusion volume is calculated as: Volume (mL) = Total Dose (g) × (100 / Concentration %).
Common Dosing Protocols
IVIG dosing varies by indication. The calculator supports the following common protocols:
| Indication | Typical Dose (g/kg) | Frequency |
|---|---|---|
| Primary immunodeficiency (replacement therapy) | 0.4 – 0.6 | Every 3–4 weeks |
| Chronic inflammatory demyelinating polyneuropathy (CIDP) | 1.0 (loading), then 0.5 – 1.0 | Every 3–4 weeks |
| Kawasaki disease | 2.0 (single dose) | Once |
| Immune thrombocytopenia (ITP) | 1.0 | May repeat if needed |
| Guillain-Barré syndrome | 0.4 | Daily for 5 days |
Interpreting the Results
The output provides two key values:
- Total Dose (grams): The amount of immunoglobulin the patient will receive. This value is used to determine the number of vials needed based on the available product sizes (e.g., 5 g, 10 g, 20 g vials).
- Infusion Volume (mL): The total fluid volume to be infused. This is critical for setting the infusion pump and determining the infusion rate based on the prescribed duration.
Always verify the calculated dose against the specific product's prescribing information and institutional protocols. The calculator provides an estimate; clinical judgment and product-specific guidelines should always take precedence.
Important Considerations
- Patient weight: Use the patient's actual body weight unless otherwise specified by protocol. For obese patients, some protocols use ideal body weight or adjusted body weight.
- Product concentration: Confirm the concentration of the specific IVIG product being used. A 10% solution delivers the same dose in half the volume compared to a 5% solution.
- Infusion rate: The calculator does not determine infusion rate. Rate should be based on product-specific guidelines, patient tolerance, and institutional policies.
- Rounding: In practice, doses are often rounded to the nearest whole vial size. The calculator provides the exact calculated dose; you may need to adjust upward or downward based on available vial sizes.
Practical Use Cases
- Verification: Double-check dosing calculations before preparing and administering IVIG.
- Protocol adherence: Ensure the prescribed dose matches the recommended protocol for the specific indication.
- Inventory planning: Estimate the number of vials needed for a treatment session.
- Patient education: Explain to patients or caregivers the amount of medication and fluid they will receive.
Frequently Asked Questions
What does g/kg mean in IVIG dosing?
g/kg stands for grams per kilogram of body weight. It is the standard unit for prescribing IVIG. For example, a dose of 0.4 g/kg means the patient receives 0.4 grams of IVIG for every kilogram they weigh.
Should I use actual body weight or ideal body weight?
Most IVIG dosing protocols use actual body weight. However, for patients with obesity, some institutions use ideal body weight or adjusted body weight to reduce the risk of adverse effects. Always follow your institution's specific protocol.
How do I convert the total dose to the number of vials?
Divide the total dose (in grams) by the vial size. For example, if the total dose is 28 g and you have 10 g vials, you would need 3 vials (30 g total). The actual dose administered may be slightly higher than the calculated dose due to vial rounding.
What is the difference between 5% and 10% IVIG?
A 5% solution contains 5 grams of immunoglobulin per 100 mL of fluid. A 10% solution contains 10 grams per 100 mL. The 10% solution delivers the same dose in half the volume, which can reduce infusion time and fluid load for the patient.
Can this calculator be used for pediatric patients?
Yes, the calculator works for any weight. Pediatric IVIG dosing follows the same g/kg principle, though the specific indications and protocols may differ from adult dosing.