title: Pitfall in the diagnosis of ectopic pregnancy: immunocytochemical evaluation in a patient with false-negative serum beta-hCG levels.
abstract: Tubal pregnancy specimens from a patient with undetectable serum beta-hCG levels and a control case with a low beta-hCG titer by radioimmunoassay were analyzed using peroxidase-antiperoxidase immunocytochemical localization of placental proteins. The results indicated that deficient production of beta-hCG by ectopic trophoblast was responsible for false-negative pregnancy tests in one patient.
mesh_terms: D000328:Adult; D006063:Chorionic Gonadotropin / Q000097:blood*; D018997:Chorionic Gonadotropin, beta Subunit, Human; D002824:Chorionic Villi / Q000473:pathology; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D010446:Peptide Fragments / Q000097:blood*; D011247:Pregnancy; D011271:Pregnancy, Ectopic / Q000175:diagnosis*; D011863:Radioimmunoassay
chemical_list: D006063:Chorionic Gonadotropin; D018997:Chorionic Gonadotropin, beta Subunit, Human; D010446:Peptide Fragments