Pharmacokinetics service for ambulatory patients.

The use of an EMIT-based serum analysis and clinical pharmacokinetics service at a family practice medical group was evaluated. The baseline level of serum drug concentration (SDC) requests per month was determined in a six-month analysis. After the purchase of the EMIT equipment and the initiation of the service, records were maintained to evaluate the cost of providing the service and its effect on the number of assays performed. This study also determined: (1) how often the pharmacist's recommendations were followed by the physicians, (2) whether the pharmacist's predicted SDC corresponded with the actual concentration, and (3) the effect of an inservice pharmacokinetics educational program on physicians' knowledge, as determined by pre- and post-testing. The requests for SDCs were found to increase from monthly average of 18 to 47 during the first year of the program's operation. The service was found to be financially self-supporting. Family practitioners concurred with the pharmacists' recommendations 97% of the time. Through the use of pharmacokinetic equations and compliance data, the pharmacists were able to predict SDC, with 91% accuracy for compliant patients. The physicians' test scores improved from 59% to 79% after the educational program. The SDC assay service (independent of the consultation service provided by faculty members and students) was self-supporting. Assessment of compliance appears to be a necessary part of an ambulatory pharmacokinetics service in accurately predicting SDC values.