title: Analytic aspects of cyclosporine monitoring, on behalf of the IFCC/IATDMCT Joint Working Group.
abstract: The use of therapeutic drug monitoring strategies for cyclosporin (CsA) has evolved markedly in recent years since previous consensus guidelines were presented. Apart from the introduction of some new methods, the major change has been the shift away from the traditional predose/trough (C0) sample. The most popular alternative has been shown to be a 2-hour postdose (C2) sample. This has presented a challenge to clinical laboratories where typical C2 sample concentrations exceed the upper limit of the calibration range for their chosen CsA method, hence requiring an accurate dilution to be performed. Data from the Australian/New Zealand survey, as well as that in the International CsA Proficiency Testing Program, have demonstrated both a plethora of dilution protocols and resultant widespread failure of many laboratories to obtain accurate results. This paper compares data from several independent sources, pointing to international problems for reliable CsA measurement in clinical laboratories. This includes the CsA method selection criteria adopted by a large percentage of laboratories in various surveys, indicating that the least specific mFPIA methods have been widely adopted.
authors.affiliation: Department of Cardiology and Clinical Pharmacology, The Queen Elizabeth Hospital, Woodville, South Australia 5011, Australia. ray.morris@nwahs.sa.gov.au
authors.forename: Raymond G
authors.initials: RG
authors.lastname: Morris
authors.forename: David W
authors.initials: DW
authors.lastname: Holt
authors.forename: Victor W
authors.initials: VW
authors.lastname: Armstrong
authors.forename: Andrea
authors.initials: A
authors.lastname: Griesmacher
authors.forename: Kimberly L
authors.initials: KL
authors.lastname: Napoli
authors.forename: Leslie M
authors.initials: LM
authors.lastname: Shaw
mesh_terms: D001315:Australia; D016572:Cyclosporine / Q000032:analysis* / Q000378:metabolism; D016903:Drug Monitoring / Q000379:methods* / Q000592:standards; D006801:Humans; D007166:Immunosuppressive Agents / Q000032:analysis* / Q000378:metabolism; D007753:Laboratories / Q000592:standards; D009520:New Zealand; D017410:Practice Guidelines as Topic; D011786:Quality Control
chemical_list: D007166:Immunosuppressive Agents; D016572:Cyclosporine