title: An enzyme immunoassay for plasma betamethasone.
abstract: A sensitive enzyme immunoassay for plasma betamethasone was developed using betamethasone-3-(O-carboxymethyl)oxime-beta-D-galactosidase conjugate as a labelled antigen and 4-methylumbelliferyl-beta-D-galactoside as a fluorescence substrate. The performances of the enzyme immunoassay were compared with that of a radioimmunoassay using 3H-betamethasone and the same antiserum. The minimal detectable level for the enzyme immunoassay was 0.15 pg/tube or 0.15 ng/ml of plasma, which was remarkably more sensitive than the radioimmunoassay level of 10 pg/tube or 2 ng/ml of plasma. The specificity was sufficient, in particular, the cross reactivity of cortisol as 0.008%. However, the precision of the enzyme immunoassay was inferior to that of the radioimmunoassay.
mesh_terms: D001623:Betamethasone / Q000097:blood*; D003429:Cross Reactions; D005697:Galactosides; D006801:Humans; D006923:Hymecromone / Q000031:analogs & derivatives; D007124:Immunoenzyme Techniques; D008832:Microchemistry; D011863:Radioimmunoassay; D011865:Radioisotope Dilution Technique; D014316:Tritium
chemical_list: D005697:Galactosides; D014316:Tritium; D006923:Hymecromone; C026845:4-methylumbelliferyl-galactopyranoside; D001623:Betamethasone