title: Homogeneous amperometric immunoassay for theophylline in whole blood.
abstract: A homogeneous spectrophotometric EMIT immunoassay kit for the quantitation of theophylline in serum or plasma has been modified to produce a rapid, amperometric immunoassay requiring a 50 microliters whole blood sample. The basis of the detection system for the assay is the electrochemical oxidation of NADH produced by G6PDH-labelled theophylline at a potential of +150 mV vs Ag/AgCl using platinised activated carbon (PACE) electrodes. Comparison of the amperometric whole blood method with the conventional spectrophotometric plasma assay produced a reasonable correlation: y = 0.90x - 1.01, (r = 0.98, n = 12). The advantage of the new method is that simple and robust instrumentation can rapidly determine theophylline in whole blood with no sample pre-treatment or separation steps.
authors.affiliation: Department of Clinical Biochemistry, Medical School, University of Newcastle upon Tyne, UK.
authors.forename: D
authors.initials: D
authors.lastname: Athey
authors.forename: C J
authors.initials: CJ
authors.lastname: McNeil
authors.forename: W R
authors.initials: WR
authors.lastname: Bailey
authors.forename: H J
authors.initials: HJ
authors.lastname: Hager
authors.forename: W H
authors.initials: WH
authors.lastname: Mullen
authors.forename: L J
authors.initials: LJ
authors.lastname: Russell
mesh_terms: D015374:Biosensing Techniques; D001774:Blood Chemical Analysis / Q000295:instrumentation / Q000379:methods; D004582:Electronics, Medical; D017248:Enzyme Multiplied Immunoassay Technique / Q000295:instrumentation; D005069:Evaluation Studies as Topic; D006801:Humans; D009243:NAD; D010084:Oxidation-Reduction; D013053:Spectrophotometry; D013806:Theophylline / Q000097:blood*
chemical_list: D009243:NAD; D013806:Theophylline