Serum drug level utilization: a literature analysis

A literature analysis was performed to quantify and evaluate the amount of inappropriate utilization of serum drug level assays. Studies that determined appropriate use based on institution-specific criteria were extracted from the literature. Inappropriate use was categorized as to indication, sampling, or use of results. Canadian studies were isolated and compared to American studies. A total of 35 studies was identified as meeting the study criteria. The rates of inappropriate utilization of drug level assays were 34.7% for indication, 47.2% for sampling, and 40.2% for use of results. Twelve studies reported an overall average inappropriate use of 58.8%. Estimations of annual waste due to inappropriate blood level use ranged from $1,221 to $100,917 per hospital. Canadian studies reported rates of 37.2%, 52.5%, and 44.5% for the three categories, respectively, and an overall inappropriate rate of 53.3%. None of these values differed significantly from those of American studies (p greater than .1). It was concluded that there is a great deal of inappropriate drug level utilization that wastes much in terms of patient care, personnel time, and costs. A great potential exists for pharmacists to intervene and improve this area of drug utilization.