Human chorionic gonadotrophin and pregnancy-specific beta-1 glycoprotein (SP-1) in ectopic pregnancy

Human chorionic gonadotrophin (hCG) was estimated by radioreceptor assay (RRA), and beta hCG and pregnancy-specific beta 1 glycoprotein(SP-1) by radioimmunoassay (RIA) in 48 consecutive patients undergoing laparoscopy for suspected ectopic pregnancy. Twenty patients subsequently proven to have ectopic pregnancy had positive results for RIA-beta hCG, but RRA-hCG and SP-1 were negative in 3. Twenty-one nonpregnant patients had negative results for RRA-hCG and RIA-beta hCG, but one had a positive result with SP-1. Seven patients with intrauterine pregnancy had positive results in all 3 assays.