Acceptance of domiciliary theophylline monitoring using dried blood spots.

Filter paper cards incorporating dried blood spots for the measurement of theophylline concentrations were returned by 62 out of 100 asthmatic children sent kits with instructions for their collection. Analysis of the blood spots showed that 37 (61%) of the children who returned them had less than therapeutic blood theophylline concentrations, in 21 (34%) they were therapeutic, and in three (5%) they were potentially toxic. The results indicate that most asthmatic children would comply with requests for home monitoring of theophylline concentrations, and that only one third of children receiving theophylline achieved blood concentrations and that only one third of children receiving theophylline achieved blood concentrations within the therapeutic range.