Mycophenolic acid (MPA) is one of the cornerstones immunosuppressants in the setting of transplantation. Advances in the pharmacokinetic studies have uncovered the high inter and intra_individual variability of plasma mycophenolic acid level. This variability in drug concentration can cause both supra therapeutic and sub therapeutic drug plasma levels which can have hazardous results in transplant patients. To date, routine therapeutic drug monitoring of MPA has not been established in clinical practice.