Immune Globulins
Key Points
- Immune globulins are preparations of concentrated antibodies (immunoglobulins) used to provide passive immunity — immediate but temporary antibody protection.
- Rh immune globulin (RhoGAM) is administered to Rh-negative pregnant patients at 28 weeks’ gestation and within 72 hours after birth to prevent Rh isoimmunization and hemolytic disease of the newborn.
- After RhoGAM administration, antibody screens will be falsely positive for 12 weeks — document drug administration date to avoid misinterpretation.
- IVIG (intravenous immunoglobulin) provides passive immune support in primary immunodeficiency, autoimmune thrombocytopenia (ITP), and other conditions.
- Typical IVIG administration starts at 0.5 to 1 mL/kg/hour for 15 to 30 minutes, then titrates every 15 to 30 minutes up to about 3 to 6 mL/kg/hour if tolerated.
- Unlike vaccines, immune globulins do not stimulate the patient’s own antibody production — protection ends when the transferred antibodies are metabolized.
- For select post-exposure indications, IM immunoglobulin is time-sensitive and should be administered as soon as possible after exposure.
Mechanism of Action
Immune globulins are derived from pooled human plasma or developed through recombinant technology. They contain concentrated antibodies (immunoglobulins) that bind specific antigens, neutralizing them before the patient’s own immune system can mount a response.
This is passive immunity:
- Onset: Immediate — no time required for antibody production
- Duration: Temporary — weeks to months depending on preparation
- No memory response — does not train the immune system for future exposure
- Contrasted with active immunity from vaccines (which takes weeks to develop but produces memory)
Rh Immune Globulin (RhoGAM)
Indication: Prevention of Rh Isoimmunization
Rh isoimmunization occurs when an Rh-negative mother is exposed to Rh-positive fetal blood during pregnancy or delivery. If fetal blood enters maternal circulation, the mother may develop anti-Rh(D) antibodies. In a subsequent pregnancy with an Rh-positive fetus, these maternal antibodies cross the placenta and destroy fetal RBCs — causing hemolytic disease of the newborn (HDN), hydrops fetalis, or fetal death.
RhoGAM mechanism: Provides pre-formed anti-D antibodies that rapidly destroy any fetal Rh-positive RBCs that have entered maternal circulation — before the mother’s immune system can produce its own anti-D antibodies. This prevents sensitization.
Administration Schedule
| Timing | Indication |
|---|---|
| 28 weeks’ gestation | Standard antepartum prophylaxis — given to all Rh-negative pregnant patients |
| Within 72 hours after birth | Given if newborn is Rh-positive; neutralizes fetal cells from delivery |
| After spontaneous abortion, termination, or invasive procedure | Any event with risk of maternal-fetal blood mixing |
| After trauma during pregnancy | Significant abdominal trauma may cause feto-maternal hemorrhage |
Route: Intramuscular injection (standard dose: 300 mcg)
72-Hour Window
RhoGAM must be administered within 72 hours of delivery (or sensitizing event) to be effective. After 72 hours, maternal sensitization may have already occurred. Always check neonate’s blood type before administering postpartum RhoGAM.
Nursing Considerations for RhoGAM
- Confirm Rh status: Administer only to Rh-negative patients
- Confirm newborn blood type: If newborn is Rh-negative, RhoGAM postpartum dose is NOT needed (no sensitization risk)
- False-positive antibody screen: After RhoGAM administration, the indirect Coombs test (antibody screen) will be falsely positive for up to 12 weeks — document administration date clearly
- Document administration: Required for all prenatal visits to prevent repeat dosing errors
- Assess for allergy to human globulin preparations; have epinephrine available (anaphylaxis risk)
Intravenous Immunoglobulin (IVIG)
IVIG consists of pooled immunoglobulin G (IgG) from thousands of plasma donors, providing broad passive antibody coverage.
Indications:
- Primary immunodeficiency — replacement therapy when patient cannot produce own antibodies
- Immune thrombocytopenic purpura (ITP) — IVIG blocks Fc receptors on splenic macrophages, temporarily reducing platelet destruction
- Kawasaki disease — reduces coronary artery complications when given with aspirin
- Certain autoimmune neuromuscular conditions (Guillain-Barré, myasthenia gravis)
Administration:
- Administered via IV infusion over 2–6 hours
- Begin at about 0.5 to 1 mL/kg/hour for the first 15 to 30 minutes, then increase every 15 to 30 minutes per protocol up to approximately 3 to 6 mL/kg/hour if tolerated
- Pre-medicate with acetaminophen ± diphenhydramine per order — reduces infusion reactions
Adverse Effects:
| Effect | Timing | Action |
|---|---|---|
| Headache, fever, chills | During/after infusion | Slow infusion rate; treat symptomatically |
| Flushing, hypotension | During infusion | Slow or stop infusion; notify provider |
| Anaphylaxis | During infusion — especially in IgA-deficient patients | Stop infusion immediately; administer epinephrine |
| Thrombosis (rare) | Post-infusion | Monitor in high-risk patients |
| Aseptic meningitis | 24–48 hours post | Headache + photophobia + neck stiffness — notify provider |
IM Immunoglobulin for Post-Exposure Prophylaxis
Selected products are given IM after high-risk exposure (for example hepatitis A, measles, varicella, or rubella) when passive antibodies are needed quickly. Benefit decreases as exposure-to-dose interval increases, so administration should occur as soon as indicated by protocol.
Nursing Assessment
NCLEX Focus
For RhoGAM: verify Rh status of mother AND newborn before administering. The 72-hour window after delivery is critical. For IVIG: monitor vital signs throughout the infusion; have emergency medications available; pre-medicate as ordered to reduce infusion reactions.
- Assess patient’s blood type and Rh factor before RhoGAM administration
- Assess for allergy to human immunoglobulin preparations or prior infusion reactions
- For IVIG: assess vital signs before and throughout infusion; assess renal function (risk of IgA deficiency-related anaphylaxis)
- Assess recent or planned live-vaccine timing because passive antibodies may blunt response to subsequent live immunization.
Nursing Interventions
- Administer RhoGAM IM within 72 hours of delivery or sensitizing event in Rh-negative patients
- Document RhoGAM dose, lot number, site, and date — required for future antibody screening interpretation
- For IVIG infusion: begin at slow rate, increase per protocol, monitor vitals q15-30 minutes
- Keep emergency medications (epinephrine, diphenhydramine, corticosteroids) at bedside during IVIG infusion
- Educate Rh-negative patients: explain purpose of RhoGAM, confirm understanding that it protects future pregnancies
- For post-exposure IM immunoglobulin, teach that delayed dosing reduces effectiveness and reinforce follow-up timing instructions.
Related Concepts
- active-and-passive-immunity — Immune globulins provide passive immunity; understanding this distinction is essential for patient education.
- susceptible-host-and-infection-risk — IVIG is used in immunocompromised hosts to temporarily reduce infection risk.
- hypersensitivity-types-and-anaphylaxis-response — Anaphylaxis is a rare but serious risk with immunoglobulin administration.
- birth-related-complications — Hemolytic disease of the newborn results from Rh isoimmunization that RhoGAM prevents.
- conditions-limited-to-pregnancy — Rh incompatibility is managed throughout pregnancy with immune globulin therapy.
- abo-blood-group-compatibility-and-transfusion-safety — Blood type and Rh factor assessment is foundational to RhoGAM administration.
Self-Check
- A nurse is preparing to discharge an Rh-negative patient after delivery. The newborn’s blood type is O positive. What is the priority nursing action?
- A patient who received RhoGAM 4 weeks ago has a positive indirect Coombs test. Should the nurse be concerned? Why or why not?
- During IVIG infusion, a patient develops sudden hypotension and hives. What are the priority nursing actions?