IVIG: A Chameleon of a Biologic


Intravenous immunoglobulin is a cornerstone in autoimmune disease treatment.

Solve this riddle: I am a fraction of a whole, rarely the same, a long time I remain. What am I?

If your answer is intravenous immunoglobulin (IVIG), you are correct.

IVIG is a cornerstone in autoimmune disease treatment, among other conditions such as idiopathic thrombocytopenia purpura, allogenic bone transplant, and off-label use in multiple sclerosis.

The treatment is vastly different from other intravenous medications. Each preparation contains blood donor plasma from between 3000 and 10,000 different individuals. Consequently, IVIG can have unique effects on a patient’s serology tests.

A case study published in the March 2021 BMC Infectious Disease recounts an incident in which a patient presenting with thrombocytopenia received IVIG. Prior to treatment, the patient’s viral serology tests were negative for any bloodborne disease.

However, post-treatment, the blood sample contained CMV and hepatitis A antibodies. Even after retesting both blood samples, the results remained unchanged.

The patient case was not unique, with numerous studies previously reporting immune status changes following IVIG administration. Researchers even reported viewing anti-troponemal antibody and anti-toxoplasma gondii antibodies in patients after IVIG treatment. A large donor pool and different manufacturing methods may cause IVIG product variability and subsequent serological changes.

As medication experts, pharmacists can educate both patients and providers about the effect of IVIG therapy on laboratory tests. For example, pharmacists can help investigate abnormal serological results and correlate them to previous IVIG treatment. False positives may occur for several days or even weeks, depending on factors pertaining the patient, donors, and manufacturers. The authors recommend:

  • Obtaining patient histories of IVIG exposure.
  • Consulting manufacturer information.
  • Refraining from immediate serological testing following treatment.

Not identifying prior IVIG exposure before serological testing may cause harm. False positive results may create unnecessary treatments, costs, and adverse effects for patients. Therefore, health care professionals should be aware that IVIG can affect patients’ viral serology and educate patients to disclose IVIG history to all future providers.

Ms. Bieniek is a 2022 PharmD Candidate at the University of Connecticut.


Suresh J, Kyle BD. Clinical false positives resulting from recent intravenous immunoglobulin therapy: case report. BMC Infect Dis. 2021;21(1):288. Published 2021 Mar 21. doi:10.1186/s12879-021-05986-z.

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