Abstracts

RATIONALE: There is general agreement that antiepilepsy drug (AED)effects should be monitored clinically and levels ordered judiciously, instead of merely adhering to specific predefined therapeutic ranges. Despite the expense and discomfort of drawing AED levels, they remain among the most commonly ordered tests in toxicology labs. This study was designed to identify clinical areas with the highest AED ordering practices, in order to propose areas needing education regarding the appropriate use of AED levels. METHODS: All AED levels performed at the University of South Alabama laboratories were reviewed for one year, from May 1999 to May 2000. Location of ordering was categorized as inpatient, outpatient, emergency department, adult or pediatric. All levels on inpatients were reviewed and defined as justifiable if they were used for clinical decision-making. RESULTS: A total of 1352 serum levels were obtained during the year reviewed, 449 in pediatric patients and 903 in adult patients. Similar proportions of tests were obtained in adult and pediatric emergency departments (42% and 36%, respectively). Approximately half of all levels were obtained on inpatients, most commonly in adult ICU patients and least commonly in pediatric non-ICU patients. 564 levels were below the usual therapeutic range and 66 were above the usual therapeutic range. Only 6% of levels obtained were ordered as unbound fractions, but were ordered concurrently with total levels only 50% of the time. At least 2 serial daily levels were drawn in 87 inpatients, and were used to make clinical management decisions in only 62% of cases. CONCLUSIONS: Emergency and outpatient ordering of AED levels appeared justifiable in most cases, as they often yielded results on which clinical decisions could be based. Ordering patterns of AED levels were most frequently difficult to justify in the inpatient ICU setting, in both adult and pediatric patients. Free levels appeared to have been underutilized, but were often obtained without comparative total levels. Specific educational initiatives indicated by analysis of these results include: appropriate use of (1)serial daily levels and (2) free levels.