title: Everolimus method comparison between Waters MassTrak™ Immunosuppressants XE (IUO) kit and an in-house laboratory developed LC-MS/MS method in renal transplant patients.
abstract: Everolimus is an immunosuppressant drug that was approved for prophylactic use in the United States to prevent organ rejection in adult kidney and liver transplant recipients. Therapeutic drug management (TDM) is required to optimize the dose for efficacy and to minimize toxicity. Prior to the development of immunoassay reagents for everolimus, laboratory developed chromatographic methods were routinely used to support TDM for everolimus testing. However, the use of high performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS)for everolimus TDM is not widely utilized in hospitals or transplant centers due to either a lack of mass spectrometry instrumentation or resources for assay development. An everolimus reagent kit and method was developed by Waters Corporation for use on the Waters ACQUITY TQD mass spectrometer system.
  
  
  OBJECTIVE
  The purpose for this study was to evaluate the investigational use only (IUO) Waters MassTrak Immunosuppressants XE (IUO) kit on a Waters ACQUITY(®) ultra performance liquid chromatography (UPLC) coupled to an ACQUITY(®) TQD mass spectrometer and to compare this test system to a laboratory developed mass spectrometry assay for everolimus.
  
  
  METHODS
  We evaluated precision and performed a patient comparison study on 56 renal transplant patients that received everolimus against a validated in house HPLC-MS/MS method.
  
  
  RESULTS
  5-day precision was performed on two patient pooled samples and analyzed in triplicate. Total imprecision for the low patient pool (3.77 ng/mL) and high patient pool (10.87 ng/mL) was <15 %CV. Deming regression analysis was performed for the patient comparison and the linear regression equation was y=0.973x+0.03, Sy/x 0.55, and the correlation coefficient was 0.9815.
  
  
  CONCLUSIONS
  The Waters MassTrak Immunosuppressants XE (IUO) kit and method had good correlation between the concentration range of 3-15 ng/mL to the established in-house HPLC-MS/MS method.
authors.affiliation: Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT ARUP Institute for Clinical and Experimental Pathology, Salt Lake City, UT and kamisha.johnson-davis@aruplab.com.
authors.forename: K L
authors.initials: KL
authors.lastname: Johnson-Davis
authors.affiliation: ARUP Institute for Clinical and Experimental Pathology, Salt Lake City, UT and.
authors.forename: J M
authors.initials: JM
authors.lastname: Juenke
authors.affiliation: ARUP Laboratories, Salt Lake City, UT, USA.
authors.forename: R L
authors.initials: RL
authors.lastname: Thomas
authors.affiliation: ARUP Laboratories, Salt Lake City, UT, USA.
authors.forename: T
authors.initials: T
authors.lastname: Bradshaw
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D000068338:Everolimus / Q000097:blood*; D006801:Humans; D007165:Immunosuppression Therapy; D007166:Immunosuppressive Agents / Q000097:blood*; D016030:Kidney Transplantation; D011933:Reagent Kits, Diagnostic; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D007166:Immunosuppressive Agents; D011933:Reagent Kits, Diagnostic; D000068338:Everolimus