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.