Objectives:To establish a candidate reference measurement procedure based on isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) for cyclosporin A, tacrolimus, sirolimus, and everolimus measurements in human whole blood.Methods:The isotope labeled cyclosporine A, tacrolimus, sirolimus, and everolimus were selected as the internal standards. Samples were accurately weighed while protein precipitation and solid phase extraction were selected for the sample preparation. The standard curve method was applied for quantification. The ultra-high liquid chromatography coupled with triple quadrupole mass spectrometer was used for analysis. The specificity, matrix effect, detection limit, quantification limit, precision, accuracy, and uncertainty of the method were evaluated.Results:The method showed good selectivity and specificity. No apparent interferences or matrix effects were found in the target analyte measurements. The detection limits and quantification limits of cyclosporin A, tacrolimus, sirolimus and everolimus met clinical requirements. Intra-batch coefficients of variation ( CV) were from 1.4% to 1.8% for CSA, from 1.7% to 2.8% for TAC, from 1.3% to 3.7% for SRL and from 2.3% to 3.2% for EVR, and total CVs were from 1.8% to 2.9% for CSA, from 1.7% to 3.8% for TAC, from 2.6% to 4.7% for SRL and from 3.5% to 4.6% for EVR. The relative recoveries were from 97.9% to 100.3% for CSA, from 98.4% to 103.1% for TAC, from 99.4% to 102.0% for SRL and from 98.3% to 99.4% for EVR, and the relative expanded uncertainties at four concentrations were from 4.2% to 4.4% for CSA, from 1.5% to 2.4% for TAC, from 4.4% to 4.9% for SRL and from 2.2% to 2.7% for EVR. Conclusion:A candidate reference measurement procedure for the cyclosporine A, tacrolimus, sirolimus, and everolimus in human whole blood was established by ID-LC-MS/MS.