title: Differences in the slopes of dose-response curves measuring pregnancy specific beta 1-glycoprotein (SP1) by means of radioimmunoassay.
abstract: Variants of pregnancy specific beta 1-glycoprotein have been described previously. These variants seem to cause artificially low levels when measured by radioimmunoassay. We demonstrate that sera with indistinct precipitates in electroimmunoassay give less steep dose-response curves in radioimmunoassay than do sera with well defined precipitates. Until parallel dose-response curves are demonstrated for all variants, previously published data must be treated with reserve.
mesh_terms: D011232:Chemical Precipitation; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007120:Immunochemistry; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000032:analysis*; D011268:Pregnancy-Specific beta 1-Glycoproteins / Q000032:analysis*; D011863:Radioimmunoassay
chemical_list: D011257:Pregnancy Proteins; D011268:Pregnancy-Specific beta 1-Glycoproteins