Multi-center evaluation of a commercial Kit for tacrolimus determination by LC/MS/MS

ObjectivesA multi-center evaluation (3 sites) of the LC/MS/MS MassTrak™ tacrolimus Immunosuppressants Kit (Kit) was undertaken.Design and methodsTen aspects of the analytical performance of the Kit were investigated based on FDA and CLSI guidelines.ResultsThe linear analytical range of the procedure was between 0.68 and 31.7 ng/mL. Within-run and total imprecision were < 6% and < 8% (n = 240), respectively. Recoveries of tacrolimus added to clinical samples that contained between 5 and 10 ng/mL of tacrolimus before addition were 99, 102 and 105% at 5.0, 10 and 20 ng/mL, respectively. Comparison of in-house and Kit procedures in samples from liver (n = 50–58) or kidney (n = 50 or 51) transplant recipients yielded method mean biases between − 2.0 and + 10.7% at 5 and 15 ng/mL.ConclusionsThis evaluation indicates that the Kit is suitable for the monitoring of tacrolimus in kidney and liver transplant recipients.