264 - Cyclosporin A dosage: A comparison between FPIA (Fluorescent Polarized Immunoassay) and CLIA (Chemo Luminescent Immuno Assay) methods

Autor(s): A. Colatutto, M. Miatton, G. Barbina, U. Qualizza, L. Isola, E. Gianoli, F. Sirianni, B. Della Vedova, C. Lazzi, P. Sala

Issue: RIMeL - IJLaM, Vol. 4, N. 4, 2008 (MAF Servizi srl ed.)

Page(s): 264-270

Background. Cyclosporin A (CsA) has revolutionized the management of allografts since the early 1980s, and has been used clinically to treat numerous conditions, including uveitis, psoriasis and nephrotic syndrome. However, the drug’s narrow therapeutic window and variable pharmacokinetics have made it difficult to establish the drug’s optimal use and dosage. Therefore, it is critical to monitor CsA blood concentrations to ensure the establishment and maintenance of an appropriate dosing regimen. Methods currently in use for monitoring CsA concentration in whole blood include HPLC, EMIT, RIA, FPIA (Fluorescent Polarized Immuno Assay), and recently CLIA (Chemo Luminescent Immuno Assay). Although the HPLC method has been considered the gold standard, the new FPIA and CLIA methods have replaced HPLC because they are more suitable for small laboratories. Methods. the purpose of our study was to compare the CLIA method to the FPIA method. We tested 100 blood samples, collected in K2 EDTA, obtained from patients undergoing immunosuppressive therapy. Blood samples were collected both before, and in 16 patients two hours after drug administration of the next dose of CsA. The samples were analysed within two hours or were frozen at –20 °C. Results. the sensitivity results from the two methods were superimposed on each other. Plotting the data on Bland Altman and elaborating them by linear regression revealed very good correlation between the methods. Conclusions. we believe that the CLIA method, because of its easy and immediate execution and total automation, could replace the FPIA procedure and could be used even in small laboratories.

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