title: Immunoassay of theophylline by latex particle counting.
abstract: We set up an immunoassay by particle counting for theophylline. Theophylline concentration is assayed by its capacity to inhibit the agglutination of theophylline coated latex particles by a specific monoclonal antibody, the agglutination being enhanced by a rabbit anti-mouse IgG antiserum. The dose range is 2-64 mg/L. The cross-reactions observed with caffeine (0.3%), theobromine (0.2%), 3-methylxanthine (0.7%) and 8-chlorotheophylline (2%) are very good when compared with other published methods. Within and between-run precisions measured at low, medium and high level of the calibration curve show coefficients of variation ranging from 3.9% to 9.5%. Our assay was correlated with the Fluorescence Polarization Immunoassay (FPIA) and a correlation coefficient of 0.96 was determined for 89 samples.
authors.affiliation: Unit of Experimental Medicine, Faculty of Medicine, Catholic University of Louvain, Brussels, Belgium.
authors.forename: S M
authors.initials: SM
authors.lastname: Poncelet
authors.forename: J N
authors.initials: JN
authors.lastname: Limet
authors.forename: J P
authors.initials: JP
authors.lastname: Noel
authors.forename: M C
authors.initials: MC
authors.lastname: Kayaert
authors.forename: L
authors.initials: L
authors.lastname: Galanti
authors.forename: D
authors.initials: D
authors.lastname: Collet-Cassart
mesh_terms: D000372:Agglutination Tests / Q000379:methods; D000818:Animals; D000911:Antibodies, Monoclonal; D002138:Calibration; D003429:Cross Reactions; D006801:Humans; D007118:Immunoassay / Q000379:methods; D007840:Latex; D051379:Mice; D008807:Mice, Inbred BALB C; D013806:Theophylline / Q000097:blood*
chemical_list: D000911:Antibodies, Monoclonal; D007840:Latex; D013806:Theophylline