ABSTRACT
Since the inception of the cyclosporine (CsA) era in the field of solid organ transplantation, validation of CsA monitoring by correlation of levels in bodily fluids to dose and to prediction of clinical events has been a hotly researched subject. Wide intra-and interindividual variations in drug disposition hallmark inconsistent reliability of CsA levels for indication of drug therapy and clinical status. This chapter examines real patient data as assessed by an educated variety of methods and makes valid conclusions on assay performance as well as on choice for a pharmacokinetic parameter, which are practical for adjustment of drug therapy and assessment of clinical status. Specimens from liver and heart recipients often have large and fluctuating concentrations of metabolites, which serve to cloud the meaning of results performed according to nonspecific assays.
