Determination of blood everolimus concentrations in kidney and liver transplant recipients using the sirolimus antibody conjugated magnetic immunoassay (ACMIA).

BACKGROUND

The aim of our study was to evaluate the possible determination of everolimus concentrations using the newly-introduced sirolimus antibody conjugated magnetic immunoassay (ACMIA).

METHODS

Everolimus concentrations were determined in 100 blood samples from kidney (n = 47) and liver (n = 53) transplant recipients using the IMx sirolimus microparticle enzyme immunoassay (MEIA) from Abbott as previously described (Clin Biochem 2007;40:132-36) and sirolimus ACMIA from Siemens Healthcare Diagnostics Ltd.

RESULTS

The ACMIA everolimus values were significantly higher than those of MEIA (p < 0.001). Analogous slope and intercept values were obtained in the linear regression between the ACMIA and MEIA results when compared to the Seradyn Certican everolimus controls or the blood samples from transplant recipients. Correction of the ACMIA values using the regression equation obtained for the control material (ACMIAcorrected = 0.55 ACMIA + 1.14) led to a satisfactory relationship with the results provided by the MEIA for the patients' samples (MEIA = 1.00 ACMIAcorrected + 0.30, r = 0.905, p < 0.001).

CONCLUSIONS

The sirolimus ACMIA on the Dimension platform, which does not require manual pre-treatment of the blood samples, may be an acceptable option for therapeutic everolimus monitoring, significantly reducing technician time in comparison to other widely-used immunoassays.