The Bureau of Drug Research, Health Protection Branch I the Government of Canada, requested of the transplant nd clinical chemistry professional groups that a consensus leeting be held, to develop a “state-of-the-art” consensus aper on cyclosporune (CsA) monitoring. The often confusg scientific literature on CsA monitoring, created largely s a result of the use of different nonspecific and specific iethods for measurement of CsA, the use of different ample matrices in which the drug is measured, and the aried criteria used for defining renal toxicity or rejection ad led to this request. In response, the Canadian Society of linical Chemists in conjunction with the Canadian Translant Society planned and organized the Canadian Consenus Meeting, which was held at Minaki, Ontario, May 11 rough 13, 1990. Twenty-one scientists representing the linical, methodological, and pharmacological aspects of sA presented to 72 attendees the latest research data on iechanisnis of the immunosuppressive and nephrotoxic ctivity of CsA; immunosuppressive and nephrotoxic activies of the major human metabolites of CsA; distribution of sA between blood plasma, blood cells, and tissues; specific iethods for measuring CsA; the impact on clinical outcome I adjusting CsA dosage on the basis of results of monitorig the parent drug concentration in whole blood; CsA harmacokinetics; and methods for detecting rejection. izsed on a detailed consideration of all data pertinent to se therapeutic drug monitoring of CsA, a set of recommenations was developed, as requested by the Canadian Iealth Protection Branch, by a consensus panel consisting I the nine individuals who co-authored this paper. At the nclusion of the meeting these recommendations and the tionale for them were presented for critical review to all ho attended the meeting. During the conference there was considerable debate gardung the following: (a) the appropriateness of one mple matrix over another (whole blood, plasma, serum,