Evaluation of a Robotic Liquid Handler, Andrew+, for Sample Preparation for LC-MS/MS-Based Quantitation of Immunosuppressants in Whole Blood

Abstract

Background: Liquid chromatography/tandem mass spectrometry (LC-MS/MS)-based assays are increasingly being used for therapeutic drug monitoring (TDM) of immunosuppressive drugs (ISDs). However, many laboratories that employ LC-MS/MS assays for TDM of ISDs use manual sample preparation steps.

Methods: We implemented a semi-automated sample preparation method based on protein precipitation, using an Andrew+ liquid handler, integrated with an LC-MS/MS-based TDM assay for four ISDs (tacrolimus, sirolimus, everolimus, and cyclosporine A). The feasibility and analytical performance were analyzed and compared with those of the manual sample preparation method using 163 clinical samples.

Results: The total execution time of Andrew+-based sample preparation method was 55 minutes (including off-line centrifugation) for 48 samples. However, the hands-on time was significantly reduced than that of the manual sample preparation method. The average repeatability and within-laboratory precision of the assay were acceptable (CV ≤10%), and the results of manual and Andrew+-based sample preparation methods were equivalent.

Conclusions: The sample preparation method using the Andrew+ liquid handler was successfully integrated with LC-MS/MS-based TDM assays for ISDs. Sample preparation using Andrew+ was reproducible, standardized, and enabled excellent utilization of technical staff time. Although further optimization for full automation is still pursued, this study indicates the potential of integrating liquid handers with LC-MS/MS-based assays in the clinical setting.