Validation d'une nouvelle méthode de dosage du tacrolimus en vue de son adaptation posologique: comparaison des résultats sur automate RXL Dimension avec ceux obtenus sur Cobas-Mira

A new method to adapt tacrolimus posology in renal transplant patients Tacrolimus (FK506) is an immunosuppressive drug with a narrow therapeutic index used in renal transplant patients among whom there is a significant correlation between effectiveness/side effects and residual blood concentrations. This correlation allows patients to increase or decrease their oral dose. However, to adapt the posology, the analysis method needs to be sensitive, specific, exact, precise and particularly rapid. The objective of our work was to validate a new method (Anti-body Conjugated Magnetic Immunoassay, ACMIA) on automat RXL Dimension (Dade-Berhing) for whole blood tacrolimus monitoring and to compare with the method usually used in medical analysis laboratories (Enzyme Multiplied Immunoassay method, EMIT). Our results show an accuracy and a precision of both repeatability and reproductibility lower than 15%. A strong correlation was found (y = 0.9373 x - 1.4429 r = 0.9533) with the results obtained on Cobas-Mira when testing drug monitoring samples in actual conditions. This new method represents a reliable alternative of EMIT, given its cost effectiveness and the absence of handling errors, for adopting it for the routine determination of blood tacrolimus concentrations in renal transplant patients.