Test Details: Tacrolimus is an immunosuppressive drug that has been shown to be effective for the treatment of organ rejection following transplantation. The narrow therapeutic range of tacrolimus requires therapeutic drug monitoring to prevent transplant rejection and to minimize nephrotoxicity. Tacrolimus Chemiluminiscent microparticleimmunoassay (CMIA) is a delayed one-step immunoassay for the quantitative determination of tacrolimus in human whole blood using CMIA technology.