title: A multi-centre evaluation of the intra-assay and inter-assay variation of commercial and in-house anti-cardiolipin antibody assays.
abstract: OBJECTIVE
  To assess the intra-assay (intra-run) and inter-assay (inter-run) variation of commercial and in-house IgG and IgM anti-cardiolipin antibody (aCL) assays/kits, and to determine an appropriate maximum value for inclusion in consensus guidelines.
  
  
  METHODS
  Frozen aliquots of two patient specimens and one commercial control were sent to nine laboratories for the evaluation of eight commercial kits and one in-house assay. Intra-assay and inter-assay evaluations were performed with all three samples for IgG aCL, and one patient specimen for IgM aCL.
  
  
  RESULTS
  The IgG and IgM aCL values varied considerably between the nine assays/kits. The majority of assays/kits demonstrated less than 20% intra-assay and inter-assay variation, with lower intra-assay and inter-assay variation observed with the commercial control. Single calibrator assays were not consistently associated with higher inter-assay variation than multi-point calibrator assays.
  
  
  CONCLUSIONS
  An inter-assay coefficient of variation of 20% was determined to be an appropriate maximum value for inclusion in the Australasian aCL Working Party consensus guidelines. Improved standardisation between different assay/kits is still required.
authors.affiliation: Division of Immunology, Queensland Health Pathology Services, Princess Alexandra and Royal Brisbane Hospitals, Qld, Australia. richard_wong@health.qld.gov.au
authors.forename: Richard
authors.initials: R
authors.lastname: Wong
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Favaloro
authors.forename: Wendy
authors.initials: W
authors.lastname: Pollock
authors.forename: Robert
authors.initials: R
authors.lastname: Wilson
authors.forename: Michelle
authors.initials: M
authors.lastname: Hendle
authors.forename: Stephen
authors.initials: S
authors.lastname: Adelstein
authors.forename: Karl
authors.initials: K
authors.lastname: Baumgart
authors.forename: Paul
authors.initials: P
authors.lastname: Homes
authors.forename: Stuart
authors.initials: S
authors.lastname: Smith
authors.forename: Richard
authors.initials: R
authors.lastname: Steele
authors.forename: Allan
authors.initials: A
authors.lastname: Sturgess
authors.forename: David
authors.initials: D
authors.lastname: Gillis
mesh_terms: D017153:Antibodies, Anticardiolipin / Q000032:analysis*; D001315:Australia; D019411:Clinical Laboratory Techniques / Q000592:standards*; D032921:Consensus; D004797:Enzyme-Linked Immunosorbent Assay / Q000592:standards; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis; D007075:Immunoglobulin M / Q000032:analysis; D007753:Laboratories / Q000592:standards*; D011785:Quality Assurance, Health Care; D011933:Reagent Kits, Diagnostic / Q000592:standards*; D015203:Reproducibility of Results
chemical_list: D017153:Antibodies, Anticardiolipin; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D011933:Reagent Kits, Diagnostic