title: Clinical utility of automated chemiluminescent antiphospholipid antibody assay.
abstract: BACKGROUND
  The threshold for clinically relevant levels of antiphospholipid (aPL) antibodies for the diagnosis of antiphospholipid syndrome (APS) remains a matter of debate. As new technologies for antibody detection are introduced, their performance characteristics must be clearly understood and compared to traditional assays.
  
  
  OBJECTIVE
  To assess the analytical performance and clinical utility of fully automated anticardiolipin (aCL) and anti-β2 glycoprotein I (aβ2GPI) chemiluminescent immunoassays (CIA) in comparison to the traditional ELISA tests.
  
  
  METHODS
  Samples from 220 autoimmune patients were studied (primary APS - 74; secondary APS - 47, systemic lupus erythematosus (SLE) without APS - 99). All samples were tested for IgG and IgM aCL and β2GPI antibodies using both CIA and ELISA, and for lupus anticoagulant (LAC).
  
  
  RESULTS
  Good qualitative agreement and quantitative correlation were found between methods in regard to individual antibodies and their categories (profiles). All assays showed good clinical performance in APS, and strong correlation with APS-related clinical symptoms. Importance of determining individual laboratory 99 percentile values for a healthy population as normal cut-off values was shown. Additionally, based on a clinical approach, this study has established the low/medium threshold for QUANTA Flash aCL IgG and IgM assays.
  
  
  CONCLUSIONS
  This study showed good clinical performance and strong correlation of the new automated CIA aPL assays with APS clinical symptoms. It also enabled us to determine the corresponding low/medium antibody threshold for the aCL antibody methods with different unit types.
authors.affiliation: Department of Medicine, Jagiellonian University Medical College, Kraków, Poland.
authors.forename: Teresa
authors.initials: T
authors.lastname: Iwaniec
authors.affiliation: Department of Medicine, Jagiellonian University Medical College, Kraków, Poland.
authors.forename: Marcin P
authors.initials: MP
authors.lastname: Kaczor
authors.affiliation: Department of Medicine, Jagiellonian University Medical College, Kraków, Poland.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Celińska-Löwenhoff
authors.affiliation: Department of Medicine, Jagiellonian University Medical College, Kraków, Poland.
authors.forename: Stanisław
authors.initials: S
authors.lastname: Polański
authors.affiliation: Department of Medicine, Jagiellonian University Medical College, Kraków, Poland. Electronic address: mmmusia@cyf-kr.edu.pl.
authors.forename: Jacek
authors.initials: J
authors.lastname: Musiał
mesh_terms: D017153:Antibodies, Anticardiolipin / Q000032:analysis / Q000276:immunology*; D016736:Antiphospholipid Syndrome / Q000276:immunology*; D005260:Female; D006801:Humans; D008163:Luminescent Measurements / Q000379:methods*; D008297:Male
chemical_list: D017153:Antibodies, Anticardiolipin
keywords: Antiphospholipid antibodies; Antiphospholipid syndrome; Chemiluminescent immunoassays; Enzyme-linked immunosorbent assay; Systemic lupus erythematosus