Objectives: Current therapeutic drug monitoring methods for sirolimus require a manual pre-treatment step and batch analysis. We describe and validate a no-pretreatment, random access sirolimus assay for the Dimension® RxL clinical chemistry system from Siemens Healthcare Diagnostics Inc. Design and methods: Whole blood samples from renal transplant patients prescribed sirolimus were analyzed by the LC-MS/MS reference method, Abbott IMx and Dimension RxL methods in accordance with CLSI recommendations. Results: The Dimension sirolimus assay had a functional sensitivity of 2.0 ng/mL and repeatability and within-laboratory imprecision less than 12.6% at 3 ng/mL and less than 5% at 11-12 ng/mL. Least squares linear regression demonstrated the following relationships: RxL = 1.20(LC-MS/MS) - 0.70, r = 0.95 and RxL = 1.33(IMx) - 0.75, r = 0.96. Conclusions: The Dimension sirolimus assay correlates well with the LC-MS/MS reference and IMx immunoassay methods and has the advantage of random access analysis without a manual pre-treatment step.
- Dimension RxL
- Random access