SERUM HUMAN CHORIONIC-GONADOTROPIN MEASUREMENT IN THE DIAGNOSIS OF ECTOPIC PREGNANCY WHEN TRANSVAGINAL SONOGRAPHY IS INCONCLUSIVE

Objective: To assess the accuracy of initial and repeated serum hCG me asurements in the diagnosis of ectopic pregnancy (EP) in patients in w hom transvaginal sonography is inconclusive and to evaluate whether pa tient characteristics influence the accuracy of serum hCG measurements . Design: Prospective study. Setting: Two large teaching hospitals in Amsterdam, the Netherlands. Patient(s): Three hundred fifty-four conse cutively seen pregnant patients with suspected EP and inconclusive tra nsvaginal sonographic findings. Intervention(s): Serum hCG measurement s. Main Outcome Measure(s): The performance of repeated serum hCG meas urements in the diagnosis of EP was evaluated through the analysis of receiver operating characteristic curves. Result(s): Initial serum hCG measurements were more diagnostic in conjunction with sonographic evi dence of an ectopic mass or fluid in the pouch of Douglas than in the absence of sonographic abnormalities. On repeated measurement, the cou rse of the serum hCG concentration provided more diagnostic informatio n than did the absolute serum hCG concentration 2 and 4 days after the start of the diagnostic process. Conclusion(s): The interpretation of serum hCG measurements should depend on additional findings at tr;tra nsvaginal sonography. A cutoff level of 1,500 IU/L is recommended for patients with an ectopic mass or fluid in thr pouch of Douglas; in pat ients without these findings, the cutoff level should be at least 2,00 0 IU/L. Four days after the start of the diagnostic process, any rise in the serum hCG concentration makes the diagnosis of EP very likely. (Fertil Steril(R) 1998;70:972-81. (C) 1998 by American Society for Rep roductive Medicine.).