Improving outcomes in therapeutic drug monitoring--a case history

A case history describes quality improvement initiatives undertaken by the Laboratory, the Pharmacy, and the Department of Nursing at Children's Medical Center in Dallas, Texas, a 266-bed pediatric teaching hospital affiliated with the University of Texas Southwestern Medical School. The initial purpose of the study was to correct problems identified by a retrospective review of randomly selected patient charts. The problems included laboratory schedules for drug assays, the timing and documenting of blood collections, the reporting of toxic results to physicians, and the interpreting of serum drug concentrations. The major changes in the program included increased frequency of testing in the laboratory, educating nurses as to sample collection guidelines, introducing a clinical pharmacy consultation service, daily reporting of all drug levels to the pharmacy from the laboratory computer, and reporting toxic levels to the clinical pharmacist who then notified the physician and offered a consult. The study then began to focus on attempting to monitor the service related to outcome indicators. Outcome data included a comparison of test volumes (15.7% decrease), tests per adjusted patient day (15.4% decrease), and tests per patient day of therapy for aminoglycosides (gentamicin decreased 6.8%) before and after the changes were implemented. Data also included aminoglycoside tests reported as therapeutic and as toxic. Plans for further improvement have been identified and include differentiating peak and trough serum drug concentrations for aminoglycosides, possibly developing protocols for vancomycin and cyclosporine monitoring, continuing to educate laboratory technologists and nurses, and continuing to monitor usage and outcome indicators.