Considerations for monitoring cyclosporine in transplant recipients

Cyclosporine (CsA) monitoring has remained controversial since the advent of the use of CsA in organ transplantation in the early 1980s. This article attempts to clarify for the clinical laboratory worker many of the vagaries associated with CsA monitoring by considering choice of sample matrix, the nature of metabolites, the technical specifications of the assay techniques used for therapeutic monitoring of CsA, comparison of results assessed by the various assays, and the pharmacokinetic considerations associated with choice of sampling time. Expectations for the degree of clinical usefulness achievable for CsA levels through further improvement in assay methodologies are also discussed.