Prompt diagnosis of ectopic pregnancy in an emergency department setting

To evaluate quantitative hCG measurements and transvaginal ultrasound in the diagnosis of ectopic pregnancy in patients presenting to the emergency department.

A discriminatory zone for detecting the presence or absence of an intrauterine pregnancy by transvaginal ultrasound was established prospectively. Women presenting to the emergency department were evaluated prospectively using a diagnostic algorithm consisting of clinical examination, quantitative serum hCG, and transvaginal ultrasound. Finally, ectopic pregnancies diagnosed over a 22-month period were evaluated prospectively.

All viable intrauterine pregnancies were identified in those subjects with hCG levels of 1500 mIU/mL (First International Reference) or greater. One thousand two hundred sixty-three subjects were evaluated prospectively; 59.8% were diagnosed with intrauterine pregnancy, 26.8% with spontaneous abortion, and 7.8% with ectopic pregnancy. At presentation, 13.2% of intrauterine pregnancies were diagnosed by clinical examination, whereas 82.9% were diagnosed by transvaginal ultrasound. Only 4% of normal intrauterine pregnancies were not confirmed on initial visit. Of 205 ectopic pregnancies diagnosed, 81.5% were hemodynamically stable; of these, 49.1% were diagnosed on initial presentation. Of all ectopics, 59% never reached an hCG level of 1500 mIU/mL and 35.8% had an hCG lower than the level at presentation. This protocol diagnosed ectopic pregnancies with a sensitivity of 100% and a specificity of 99.9%.

A protocol of quantitative hCG levels (available within hours of presentation to an emergency department) combined with transvaginal ultrasound is effective in diagnosing ectopic pregnancy.