title: Performance characteristics of a no-pretreatment, random access sirolimus assay for the Dimension RxL clinical chemistry system.
abstract: OBJECTIVE
  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.
  
  
  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.
authors.affiliation: Department of Pathology and Immunology, Division of Laboratory and Genomic Medicine, Washington University School of Medicine, Box 8118, 660 S. Euclid Avenue, St. Louis, MO 63110, USA.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Cervinski
authors.forename: Show-Hong
authors.initials: SH
authors.lastname: Duh
authors.forename: Karl G
authors.initials: KG
authors.lastname: Hock
authors.forename: Jeffery
authors.initials: J
authors.lastname: Gray
authors.forename: Tie Q
authors.initials: TQ
authors.lastname: Wei
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Kilgore
authors.forename: Robert H
authors.initials: RH
authors.lastname: Christenson
authors.forename: Mitchell G
authors.initials: MG
authors.lastname: Scott
mesh_terms: D001681:Biological Assay / Q000379:methods* / Q000592:standards*; D002624:Chemistry, Clinical / Q000379:methods* / Q000592:standards*; D016903:Drug Monitoring / Q000379:methods* / Q000592:standards*; D006801:Humans; D020123:Sirolimus / Q000097:blood*
chemical_list: D020123:Sirolimus