title: Development of an Abbott ARCHITECT cyclosporine immunoassay without metabolite cross-reactivity.
abstract: OBJECTIVE
  We investigated the mechanism by which the ARCHITECT cyclosporine (CsA) chemiluminescent microparticle immunoassay (CMIA) eliminates cross-reactivity to CsA metabolites AM1 and AM9, despite its use of a monoclonal antibody which shows cross-reactivity in fluorescence polarization immunoassays.
  
  
  METHODS
  The CMIA was accomplished by incubating an extracted blood sample with magnetic microparticles coated with a very low amount of anti-CsA antibody. After a wash step the microparticles were incubated with a chemiluminescent CsA tracer, followed by a second wash step and measurement of chemiluminescence. The reagent concentrations of salt and detergent were optimized to maximize CsA binding and minimize metabolite interference.
  
  
  RESULTS
  Elimination of CsA metabolite cross-reactivity was shown using purified metabolites and blood samples containing native CsA metabolites. The CMIA demonstrated precision and sensitivity acceptable for use in a clinical setting.
  
  
  CONCLUSIONS
  We conclude that it is possible to eliminate CsA metabolite immuno-cross-reactivity by careful assay design.
authors.affiliation: Abbott Diagnostics, Abbott Park, IL 60064, USA.
authors.forename: Elaine M
authors.initials: EM
authors.lastname: Brate
authors.forename: David M
authors.initials: DM
authors.lastname: Finley
authors.forename: Jonathan
authors.initials: J
authors.lastname: Grote
authors.forename: Shelley
authors.initials: S
authors.lastname: Holets-McCormack
authors.forename: Pan F
authors.initials: PF
authors.lastname: Ozaeta
authors.forename: David
authors.initials: D
authors.lastname: Pacenti
authors.forename: Joan E
authors.initials: JE
authors.lastname: Peart
authors.forename: Ryan E
authors.initials: RE
authors.lastname: Piktel
authors.forename: Carol S
authors.initials: CS
authors.lastname: Ramsay
authors.forename: Kevin R
authors.initials: KR
authors.lastname: Rupprecht
authors.forename: Sylvia C
authors.initials: SC
authors.lastname: Saldana
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Spring
authors.forename: Sergey Y
authors.initials: SY
authors.lastname: Tetin
authors.forename: Beth C
authors.initials: BC
authors.lastname: Trudeau
authors.forename: Phil
authors.initials: P
authors.lastname: Wang
authors.forename: Helen
authors.initials: H
authors.lastname: Xie
mesh_terms: D000911:Antibodies, Monoclonal; D003429:Cross Reactions; D016572:Cyclosporine / Q000097:blood* / Q000378:metabolism; D006801:Humans; D007118:Immunoassay / Q000379:methods* / Q000592:standards; D008163:Luminescent Measurements; D012680:Sensitivity and Specificity
chemical_list: D000911:Antibodies, Monoclonal; D016572:Cyclosporine