Serum specific protein 1 and beta-human chorionic gonadotropin concentrations in patients with suspected ectopic pregnancies.

To determine the predictive value of serum specific protein 1 (SP1) and beta-human chorionic gonadotropin (beta-hCG) in the diagnosis of ectopic pregnancy, blood was sampled from 82 patients referred for suspected early extrauterine pregnancies. Serum concentrations of SP1 and beta-hCG were determined by EIA and RIA. All patients with early pregnancies had detectable SP1 and beta-hCG levels. An intrauterine pregnancy was found in six patients, and an ectopic pregnancy was confirmed by surgical explorations in 32 of these women. The remaining 40 women had other non-pregnancy related complaints. In all pregnant patients, the beta-hCG RIA and SP EIA determinations were also found positive. This study demonstrates the high predictive value of serum SP1 and beta-hCG determinations with an acceptable sensitivity and specificity in the diagnosis of suspected early ectopic pregnancies. In addition, the practicability and the easy performance of the enzymoimmunometric SP1 determination renders this test superior over the radioimmunoassay for beta-hCG determination.