Passive transfusion of human chorionic gonadotropin from plasma donated during pregnancy

Although fresh frozen plasma (FFP) prepared from autologous blood donated during pregnancy has frequently been given to homologous recipients at our institution, one transfusion resulted in an unanticipated diagnostic dilemma. A 31-year-old woman with disseminated intravascular coagulation of unclear etiology was transfused with multiple units of FFP, including 2 from pregnant autologous donors. A serum human chorionic gonadotropin (HCG) assay, performed because of the possibility that the patient's illness was a complication of unrecognized pregnancy, was positive using a blood sample drawn 7 h after the transfusions. An extensive evaluation was completed before the possibility of passive transfer of hormone from blood products was considered. Retrospective testing of serum samples established that HCG appeared in the patient's serum only after the first FFP transfusion from a pregnant autologous donor. In 8 other recipients of 1 or 2 units of FFP from pregnant autologous donors, post-transfusion HCG levels ranged between 96 and 1,750 mIU/ml. Of 15 recipients of packed red blood cells from pregnant autologous donors, only patients with renal failure or recipients of multiple units developed positive HCGs, which were always less than or equal to 85 mIU/ml. The differential diagnosis of a positive pregnancy test in a recently transfused individual should include the possibility of passively acquired hormone.