P787 Aims: Routine monitoring of cyclosporine and tacrolimus (FK) levels is necessary to minimize adverse slide effects and to ensure effective immunosuppression. Similarly, interest in mycophenolate (MMF) monitoring is increasing. By contrast to traditional methods, the V-Twin analyser (Vital SC, Netherlands) conceived for EMIT technologies (Dade Behring Laboratories) is proposed to determine C0 and C2 cyclosporin levels using specific calibrator and without any dilution, and also tacrolimus and mycophenolate levels using the same method. Methods: Cyclosporine (C0, n=184 and C2, n=55) and FK (n=125) EMIT assays were compared to RIA Ciclosporine assay (DiaSorin Laboratory) and to MEIA Tacrolimus assay (Abbott Laboratory) respectively. In addition, the feasibility of MMF EMIT assay was evaluated. 303 transplant patients (204 kidney, 65 liver, 8 heart and 26 bone marrow transplantation) were included in this study Results For all parameters tested (C0, C2, FK and MMF), mean of the within run and between days total imprecision werelower than 10%, coefficient of linearity r2>0.99. For cyclosporine kit, range of linearity was between 25 and 500ng/ml for C0 and 400 and 2000 ng/ml for C2 assay. Mean recoveries of an overload test, realized with Cyclosporine (Sandimum, Novartis), were 78% for cyclosporine C2, and 81% for cycloporine C0. Values obtained with clinical samples are highly correlated to RIA for C0 levels (EMIT = 0,9RIA + 3,66; R = 0,974) and for C2 levels (EMIT = 0,9943RIA - 142,27; R = 0,956). The values upper than 600ng/ml tested on Cyclosporine C0 assay with external dilution were closely related to those obtained on Cyclosporine C2 (R=0,939). Similar results were obtained with FK EMIT kit with a linearity range between 3 and 30mg/l, and a high concordance with MEIA test (EMIT = 0,988RIA + 1,09; R= 0,96). Finally, preliminary results with MMF assay including analytical performances and serum determination in 59 serum ranging from 0.1 to 30 μg/ml show that the follow-up can easily be made in routine. Conclusions: In conclusion, the V-Twin system is an usefull tool to routine monitoring with a single method for C0 and C2 cyclosporine, tacrolimus and mycophenolate levels.