Development and evaluation of a new test kit for determination of immunosuppressants in blood by UHPLC-MS/MS

In this study, we have developed and validated a new test kit that applied pure solvents instead of blood samples for determination of immunosuppressant drugs in blood by ultra high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). We have used commercially available quality control samples to verify this new test kit, and the results showed that the performance of our new kit was comparable with commercially available kits by immunoassays. The new test kit is pure solvent-based, which saves the cost and can be directly loaded without pre-treatment, thus shortening the detection time. The agreement between pure solvent-based kit and blood-based kit was also evaluated by Bland-Altman plot and two-tailed Student's T-test. For 97.08% of the 137 Tacrolimus clinical samples, the concentration difference between these two kits was laid within 20% of the mean concentration. The concentrations of 12 cyclosporine samples and 15 sirolimus samples obtained by both kits showed no significant difference evaluated by the two-tailed Student's T-test. These results further demonstrated the good agreement between these two types of test kits. Meanwhile, our pure solvent-based test kit could be stored stably for 14 weeks at -30 °C. Therefore, the newly developed pure solvent-based test kit can be used for detecting the whole blood immunosuppressant concentration and therapeutic drug monitoring of immunosuppressants.