Falsely elevated human chorionic gonadotropin leading to unnecessary therapy

Background: Analysis of serum beta -hCG aids diagnosis and treatment of intrauterine pregnancies, ectopic gestations, and gestational trophoblastic neoplasia. beta -hCG concentrations are specific for trophoblastic tissue, thus are rarely questioned. Cases: An 18-year-old nullipara had bleeding and a positive beta -hCG. Ultrasound identified no pregnancy. She passed tissue and stopped bleeding. Serum beta -hCG remained elevated despite uterine curettage and three courses of methotrexate. Results of urine beta -hCG were negative, as was reference laboratory serum assay. A 31-year-old nullipara had a spontaneous abortion, but serum beta -hCG remained elevated. Uterine curettage found secretory endometrium, yet elevated serum beta -hCG persisted. Urine beta -hCG was negative, as was reference laboratory serum assay. Conclusion: Patients with histories incongruent with serum beta -hCG findings should have urine beta -hCG analysis.