Good correlation between tacrolimus concentrations using improved CMIA on the Alinity i analyzer and LC-MS/MS method from a reference laboratory but unexpected negative bias with another LC-MS/MS method from a different reference laboratory.

Because of good correlation of tacrolimus concentrations using the CMIA and LC-MS/MS from reference laboratory A, our long-term reference laboratory for drug analysis, we concluded that the CMIA on the Alinity i can be used for therapeutic drug monitoring of tacrolimus.