Theophylline serum concentrations in ambulatory patients with chronic obstructive pulmonary disease

A two-part study was designed to investigate the application of theophylline serum concentration data at a Veterans Administration Medical Center. The investigation was unique in its use of ambulatory patients instead of hospitalized patients as study subjects for assessing the use of laboratory tests. As has been found in other studies that examined different drugs and involved hospitalized subjects, this investigation discovered significant problems in the ordering, application, and documentation of these data when judged against established criteria. There was no significant difference in the appropriate use of these drugs between physicians specializing in pulmonary versus general medicine. Of clinical importance also are the findings that confirm a positive correlation between the proper use of these tests and improvement in patient outcome, and the demonstrated relationships between clinical symptoms and subtherapeutic and toxic serum concentrations of theophylline.