Comparison of theophylline concentrations in venous blood and capillary blood in asthmatic children.

Twenty children, five to 16 years old, diagnosed as having asthma, were studied to compare the serum concentrations of theophylline obtained by standard venipuncture with capillary concentrations obtained by finger lancet. The mean theophylline concentration in venous samples was 9.27 mg/L and in capillary samples was 9.26 mg/L. Comparison by the paired t-test showed no statistical difference between kinds of samples. When surveyed as to their preference, nine patients preferred the venous method, five the capillary method, and six had no preference.