False Positive Syphilis Serology after IVIG Administration

We report a case of a 44 year old female with Systemic Lupus Erythematosus (SLE) who received intravenous immunoglobulin (IVIG) and was subsequently found to have positive Immunoglobulin G (IgG) syphilis serology. The chronology of the positive serologies, with documented testing prior to IVIG administration being negative, suggests that the tests represent a false positive result secondary to the passive transfer of the immunoglobulin component. While the phenomenon of multiple positive serologies in a short time span after IVIG administration has been described, it is rarely recognized, and poses risks to the patient through unnecessary treatment.