title: Accuracy and precision of methods for theophylline measurement in physicians' offices.
abstract: We tested the accuracy and precision of five theophylline methods intended for use in physicians' offices. The Syntex AccuLevel, Ames Seralyzer, and 3M Diagnostics TheoFAST methods were less reproducible (CVs 6.3% to 9.2%) than the Abbott Vision and Kodak DT-60 (CVs 2.2% to 3.3%). Caffeine interfered with the Vision, Seralyzer, and AccuLevel methods, and theobromine interfered with the Vision, Seralyzer, and TheoFAST methods. Only the DT-60 method was free from interference from any of the 24 compounds tested. Results by all methods correlated well with those by the HPLC comparison method (Clin Chem 1981;27:1931-3) and by the Abbott TDx method for assay of 100 serum (or, when appropriate, paired whole-blood) samples. The frequency of sample results differing from the comparison method by greater than 2.0 mg/L was as follows: TDx, 11%; Vision (serum), 12%; Vision (whole blood), 18%; DT-60, 14%; AccuLevel, 18%; Seralyzer, 25%; and TheoFAST, 31%. The Kodak DT-60 method was the most nearly accurate and precise among these physician's office methods. Some physician's office methods for theophylline analysis are not adequate to guide dosage adjustments.
authors.affiliation: Department of Pathology, University of Maryland School of Medicine, Baltimore 21201.
authors.forename: J D
authors.initials: JD
authors.lastname: Cook
authors.forename: G E
authors.initials: GE
authors.lastname: Platoff
authors.forename: T R
authors.initials: TR
authors.lastname: Koch
authors.forename: E C
authors.initials: EC
authors.lastname: Knoblock
mesh_terms: D006801:Humans; D009819:Office Visits; D011933:Reagent Kits, Diagnostic / Q000592:standards*; D015203:Reproducibility of Results; D013806:Theophylline / Q000097:blood* / Q000592:standards
chemical_list: D011933:Reagent Kits, Diagnostic; D013806:Theophylline