Improving the use of therapeutic drug monitoring.

Many studies suggest that therapeutic drug monitoring (TDM) could be used better. For example, a high proportion of TDM assays either lack an inappropriate indication or are drawn with suboptimal timing, particularly for inpatients. From a perspective of quality, undermonitoring has more potential adverse consequences than overmonitoring. Because both overuse and underuse occur, it may be possible to improve the quality of TDM while reducing its costs and, more important, to have similar effects on the quality and costs associated with caring for patients administered drugs.