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A rapid desktop theophylline assay. Evaluation of use in clinical management
J L Kiely1, G Lawless, S Cunningham
1Department of Respiratory Medicine, St. Vincent's Hospital, Dublin, Ireland.
Study Objectives:
To assess the practicality and precision of a simple desktop theophylline assay (Biotrack 516TM) in comparison to a standard laboratory assay system (Abbott TDxTM).
Design:
A prospective blinded paired sample study.
Setting:
The respiratory ward and outpatient 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:
Paired specimens for theophylline assay were collected simultaneously for analysis. There was a highly significant (p < 0.001) correlation between the two assay systems for both the total range studied (1.2-39.1 micrograms/mL; r = 0.98), and the clinically important range of 5-15 micrograms/mL (r = 0.95). The limits of agreement for the data by the Bland and Altman method indicated a +/-2 micrograms/mL limit for the 5-15 micrograms/mL range and a +/-2.7 micrograms/mL limit for the total range studied.
Conclusions:
The Biotrack 516 is an easy-to-use system, which provides rapid and reasonably precise measurements of serum theophylline levels. The device should be of particular value in smaller centers without an on-site laboratory assay system.
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