Therapeutic monitoring (TDM) of antiepileptic drugs (AEDs), or antiseizure medicines (ASMs) represents a pragmatic approach to the management of patients with epilepsy to assess either compliance, efficacy and toxicity. Dose adjustments based on drug concentrations detected in biological fluids allow physicians to optimize and personalize the pharmacologic regimens for the single patient. TDM of AEDs has become increasingly popular since the 1970s because it is difficult to identify the optimal drug dose for each patient and because AEDs concentrations correlate better than dose with clinical effects. This document aims to suggest reference intervals to harmonize the pharmacokinetic activity among Italian Laboratories in the monitoring of AEDs plasma exposures according to recent international literature and guidelines. [ABSTRACT FROM AUTHOR]