1. Evaluation of Serum Theophylline Measurement using a Test-strip
Victor E. Turkington, M. Sc., Amin A Nanji, M.D. 
CHEST 
Volume 89, Issue 4, Pages (April 1986)
DOI: /chest b
Copyright © 1986 The American College of Chest Physicians Terms and Conditions

2. Figure 1
Comparison of serum theophylline levels by the test-strip and reference (Abbott TDX) methods. Test-strip = 1.21(TDX) – 0.4.
CHEST  , DOI: ( /chest b)
Copyright © 1986 The American College of Chest Physicians Terms and Conditions