title: Effect of oral contraceptive used by technician on sensitivity of progesterone radioimmunoassay.
abstract: Gonadotropin and steroid radioimmunoassays (RIAs) have been run in our laboratory for the past 6 years. Recently, the progesterone RIA was unpredictable when performed by one technician. After checking the mechanics and reagents, it was discovered that the technician had changed from Ortho Novum 1 + 50 to Ovral about the time the RIA became erratic. Standard curves of progesterone RIAs performed while the technician was taking either Ortho Novum 1 + 50 or Ovral, or on no contraceptive are reported. The data suggest that a probably exhaled metabolic product of norgestrel, the synthetic progestin in Ovral, interferes with the progesterone RIA and indicate an additional variable investigators must eliminate in performing RIAs.
mesh_terms: D003276:Contraceptives, Oral / Q000378:metabolism; D003951:Diagnostic Errors; D005260:Female; D006801:Humans; D013677:Medical Laboratory Science; D009644:Norgestrel / Q000378:metabolism; D011374:Progesterone / Q000032:analysis*; D011863:Radioimmunoassay / Q000592:standards
chemical_list: D003276:Contraceptives, Oral; D009644:Norgestrel; D011374:Progesterone