RAPID MODIFICATION OF BETA-HCG RADIOIMMUNOASSAY - USE AS AN AID IN DIAGNOSIS OF ECTOPIC PREGNANCY

Abstract

Over half the patients with proven ectopic pregnancies have negative urinary slide or tube pregnancy tests at the time they present with symptoms. Because of the morbidity and mortality associated with unrecognized ectopic pregnancy, the need for an accurate, rapid, sensitive and specific method for measuring low levels of human chorionic gonadotropin (hCG) is apparent. A 3 h radioimmunoassay (RIA) for serum hCG with a sensitivity of 5 mIU/ml was developed which utilizes an antiserum generated against the .beta. subunit of hCG, 125I-hCG for tracer purposes, a highly purified hCG standard and dioxane for separation of bound from free hormone. Blood samples were obtained from 52 patients with suspected ectopic pregnancies. Twenty-four of these patients had a surgically proven ectopic gestation. The blood samples were analyzed in the above described RIA, and in the standard (24 h) double antibody .beta.-hCG RIA. There were no false positive or false negative results by either assay. The dioxane modification of the .beta.-hCG RIA is an accurate and rapid method for confirming the diagnosis of ectopic pregnancy.