Validation of Conversion Factors for Therapeutic Drug Monitoring of Lacosamide, Lamotrigine, and Levetiracetam in Dried Capillary Blood.

Estimating serum concentrations using capillary blood concentrations is feasible and accurate for LCM and LEV over a wide concentration range, as found in clinical practice. The applicability of this method for LTG is limited by its greater variability at higher concentrations; however, acceptable results were achieved for the large proportion of patients with low and medium LTG concentrations.