Diagnosis of ectopic pregnancy: value of the discriminatory human chorionic gonadotropin zone

Obstet Gynecol. 1985 Sep;66(3):357-60.


A prospective study was conducted to test the hypothesis that the absence of an intrauterine gestational sac when the serum level of human chorionic gonadotropin (hCG) is above 6500 mIU/mL is indicative of ectopic pregnancy. A total of 383 patients who were clinically suspected to have ectopic pregnancies had pelvic ultrasound examinations with serum hCG determinations on the day of the scan. There were 217 (57%) intrauterine gestations, 104 (27%) ectopic pregnancies, and 62 (16%) spontaneous abortions. Forty-one percent of patients had an hCG level above 6500 mIU/mL. The absence of an intrauterine gestational sac at an hCG concentration above this level had a sensitivity of 100%, a specificity of 96%, a positive predictive value of 86%, a negative predictive value of 100%, and was 98% efficient, based on a 19.4% prevalence of ectopic pregnancies among this group.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abortion, Spontaneous / diagnosis
  • Chorionic Gonadotropin / blood*
  • Female
  • Humans
  • Pregnancy
  • Pregnancy, Ectopic / diagnosis*
  • Prospective Studies
  • Ultrasonography


  • Chorionic Gonadotropin