Phenytoin Drug Level Test - Phenytoin Serum Level Test

This analysis measures the serum concentration of phenytoin, an anticonvulsant drug belonging to the hydantoin class. It is a cornerstone of therapeutic drug monitoring (TDM) due to its nonlinear pharmacokinetics (overdose causes a disproportionate rise in levels) and its narrow therapeutic margin, meaning the difference between the effective and toxic doses is very small.