title: Comparison of mycophenolic acid concentrations determined by a new PETINIA assay on the dimension EXL analyzer and a HPLC-UV method.
abstract: OBJECTIVE
  Mycophenolic acid requires routine therapeutic drug monitoring. We evaluated the suitability of a new PETINIA (particle enhanced turbidimetric inhibition immunoassay) assay on the Dimension EXL analyzer for monitoring of mycophenolic acid by comparing values obtained by this assay with a HPLC-UV method.
  
  
  METHODS
  Mycophenolic acid concentrations determined in sera of 60 organ transplant recipients using high performance liquid chromatography combined with ultraviolet detection (HPLC-UV, reference method) and the new immunoassay on the Dimension RxL analyzer.
  
  
  RESULTS
  The within and between run precision of the new PETINIA assay was <10%. The assay was linear for a mycophenolic acid concentration up to 30μg/mL. When mycophenolic acid concentrations in 60 transplant recipients obtained by the HPLC-UV (x-axis) method were compared with corresponding values obtained by the PETINIA assay (y-axis), the following regression equation was obtained: y=1.1204 x+0.0881 (r=0.983, n=60).
  
  
  CONCLUSIONS
  If PETINIA assay is used for therapeutic drug monitoring of mycophenolic acid, caution must be exercised in interpreting serum mycophenolic acid level due to observed positive bias.
authors.affiliation: Department of Pathology, University of Texas-Houston Medical School and Laboratory Services Memorial-Hermann Hospital at Texas Medical Center, United States. Amitava.Dasgupta@uth.tmc.edu
authors.forename: Amitava
authors.initials: A
authors.lastname: Dasgupta
authors.forename: Gertie
authors.initials: G
authors.lastname: Tso
authors.forename: Loretta
authors.initials: L
authors.lastname: Chow
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods; D016903:Drug Monitoring / Q000379:methods; D006801:Humans; D007118:Immunoassay / Q000379:methods; D007166:Immunosuppressive Agents / Q000097:blood*; D009173:Mycophenolic Acid / Q000097:blood*; D009391:Nephelometry and Turbidimetry / Q000379:methods; D016377:Organ Transplantation / Q000502:physiology; D014466:Ultraviolet Rays
chemical_list: D007166:Immunosuppressive Agents; D009173:Mycophenolic Acid