Serum progesterone testing to predict ectopic pregnancy in symptomatic first-trimester patients

Ann Emerg Med. 2000 Aug;36(2):95-100. doi: 10.1067/mem.2000.108653.


Study objective: This study was conducted to prospectively measure the accuracy of serum progesterone levels to detect ectopic pregnancy.

Methods: Seven hundred sixteen symptomatic first-trimester emergency department patients with abdominal pain or vaginal bleeding at a tertiary care military teaching hospital had progesterone levels measured by radioimmunoassay with results unavailable to the treating physician. All patients were monitored until a criterion standard diagnosis of intrauterine pregnancy or ectopic pregnancy was confirmed.

Results: A 14-month derivation phase (n=399) used receiver operating characteristic curve testing to select a cutoff value of progesterone less than 22 ng/mL. A 12-month validation phase (n=317) then retested this cutoff value. Combining both phases, there were 434 (61%) viable intrauterine pregnancies, 229 (32%) nonviable intrauterine pregnancies, and 52 (7. 3%) ectopic pregnancies, of which 17 were ruptured. Sensitivity, specificity, positive predictive values, and negative predictive values (95% confidence intervals) for progesterone levels less than 22 ng/mL to detect ectopic pregnancy were 100% (94% to 100%), 27% (23% to 30%), 10% (7% to 12%), and 100% (98% to 100%), respectively.

Conclusion: Given similar disease prevalence, roughly one fourth (178/716) of symptomatic patients can be classified as low risk (0%, 95% confidence interval 0 to 2%) for having an ectopic pregnancy using a progesterone cutoff of 22 ng/mL. Whether implementation of rapid progesterone testing can safely expedite care and reduce the need for urgent diagnostic evaluation or admission remains to be determined.

Publication types

  • Clinical Trial
  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abdominal Pain / diagnosis
  • Abdominal Pain / etiology
  • Adult
  • Biomarkers / blood
  • Confidence Intervals
  • Emergency Service, Hospital
  • Female
  • Humans
  • Predictive Value of Tests
  • Pregnancy
  • Pregnancy Trimester, First
  • Pregnancy, Ectopic / blood
  • Pregnancy, Ectopic / diagnosis*
  • Progesterone / blood*
  • Prospective Studies
  • ROC Curve
  • Radioimmunoassay
  • Registries
  • Sensitivity and Specificity
  • Uterine Hemorrhage / diagnosis
  • Uterine Hemorrhage / etiology


  • Biomarkers
  • Progesterone