Assay of human chorionic gonadotrophin in the patient with a suspected ectopic pregnancy.

Assay for the beta-subunit of human chorionic gonadotrophin (HCG) in the serum of 50 patients in whom the diagnosis of an ectopic pregnancy was suspected was compared with other diagnostic methods. The urine pregnancy test was only positive in 30% and culdocentesis in 60%, whereas the beta-HCG test was positive in 96% of cases. A flow-chart for the management of the patient with a suspected ectopic pregnancy is outlined.