engleski

Comparison of cyclosporine A concentrations determined using ECLIA and FPIA methods

Background: Cyclosporine A is a potent immunosuppressant which is used as a primary agent during immunosuppressive therapy for solid organ transplants. Monitoring patient’s cyclosporine A blood concentrations is important for adjusting dosage to avoid overdose toxicity or underdose inefficiency. The aim of this study was to compare two methods for measuring cyclosporine A blood concentrations: ECLIA (electrochemiluminescence immunoassay) and FPIA (fluorescence polarization immunoassay). Materials and Methods: The concentration of cyclosporine A was measured in 24 whole blood samples of patients on cyclosporine A therapy. After manual sample preparation, cyclosporine A was determined using ECLIA (on automatic analyser Abbott Architect i100SR) and FPIA (on automatic analyser Abbott AxSYM). We compared the two analytical methods using the Passing and Bablok regression analysis (Cusum test P < 0.05 indicates significant difference from linearity). The accepted mean bias value by providers for external quality control is ±10%. Results: The regression equation according to Passing and Bablok was y = 8, 0793 + 1.0996x (95% CI for intercept was from -1.4238 to 14.6007 and 95% CI for slope was from 1.0239 to 1.1942). The mean bias value was -20.79%, and the calculated Cusum linearity test P value was 0.48. Conclusion: Passing and Bablok intercept showed that there is no constant difference between the two methods. However, the slope showed that there is a proportional difference. The Cusum test indicated no significant deviation from linearity, and the mean bias value exceeded twofold the acceptable percentage. Thus, only one method should be used to monitor patient’s cyclosporine A concentrations. Taken together, for obtaining reliable results, when monitoring patient’s drug concentrations, it is recommended to use the same analyzer as well as the same immunoassay.

comparison, cyclosporine A, Passing and Bablok regression

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