Figure 1.

CONSORT diagram of cohort creation. Exclusion criteria were applied to exclude (1) subjects who switched type of assay used during the study period and (2) subjects who underwent therapeutic drug monitoring at a small laboratory and for whom, as a result, use of the same type of assay through the entire study period could not be confirmed. Subjects were split into 2 groups according to type of assay used for tacrolimus therapeutic drug monitoring, liquid chromatography–mass spectrometry (LC-MS) or immunoassay (IA).