A RAPID DESK-TOP THEOPHYLLINE ASSAY - EVALUATION OF USE IN CLINICAL MANAGEMENT

Study objectives: To assess the practicality and precision of a simple desktop theophylline assay (Biotrack 516(TM)) in comparison to a stan dard laboratory assay system (Abbott TDx(TM)). Design: A prospective b linded paired sample study. Setting: The respiratory ward and outpatie nt clinics, the pulmonary function and biochemistry laboratories of a university teaching hospital. Patients: Sixty patients with asthma or COPD attending the respiratory service. Measurements and results: Pair ed specimens for theophylline assay were collected simultaneously for analysis. There was a highly significant (p < 0.001) correlation betwe en the two assay systems for both the total range studied (1.2-39.1 mu g/mL; r=0.98), and the clinically important range of 5-15 mu g/mL (r= 0.95). The limits of agreement for the data by the Bland and Altman me thod indicated a +/-2 mu g/mL range and a +/-2.7 mu g/mL limit for the total range studied. Conclusion: The Biotrack 516 is an easy-to-use s ystem, which provides rapid and reasonably precise measurements of ser um theophylline levels. The device should be of particular value in sm aller centers without an on-site laboratory assay system.