title: Confirmation of initial antiphospholipid antibody positivity depends on the antiphospholipid antibody profile.
abstract: BACKGROUND
  The revised classification criteria for the antiphospholipid syndrome state that antiphospholipid (aPL) antibodies (lupus anticoagulant [LAC] and/or anticardiolipin [aCL] and/or anti-β2 -glycoprotein I [aβ2 GPI] antibodies) should be detected on two or more occasions at least 12 weeks apart. Consequently, classification of patient risk and adequacy of treatment may be deferred by 3 months.
  
  
  OBJECTIVE
  In order to early classify patient risk, we evaluated whether aPL positivity confirmation is related to aPL antibody profiles.
  
  
  METHODS
  Consecutive patients referred to our center who were initially positive in one or more tests exploring the presence of aPL were tested after 3 months. During a 4-year period, 225 patients were initially positive in one or more tests, and 161 were available for confirmation after 3 months. Patients were classified as triple-positive (n = 54: LAC(+) , aCL(+) , aβ2 GPI(+) , same isotype), double-positive (n = 50: LAC(-) , aCL(+) , aβ2 GPI(+) , same isotype) and single-positive (n = 53: LAC or aCL or aβ2 GPI antibodies as the sole positive test).
  
  
  RESULTS
  Among subjects with triple positivity at initial testing, 98% (53 of 54) had their aPL profile confirmed after 12 weeks. The double-positive and single-positive groups had data confirmed in 42 of 50 (84%) and 23 of 57 (40%) subjects, respectively.
  
  
  CONCLUSIONS
  Our results show that high-risk subjects with triple-positive aPL profiles are identified early, at the time of the initial screening tests.
authors.affiliation: Clinical Cardiology, Thrombosis Center, Department of Cardiac Thoracic and Vascular Sciences, University of Padua, Padua, Italy. vittorio.pengo@unipd.it
authors.forename: V
authors.initials: V
authors.lastname: Pengo
authors.forename: A
authors.initials: A
authors.lastname: Ruffatti
authors.forename: T
authors.initials: T
authors.lastname: Del Ross
authors.forename: M
authors.initials: M
authors.lastname: Tonello
authors.forename: S
authors.initials: S
authors.lastname: Cuffaro
authors.forename: A
authors.initials: A
authors.lastname: Hoxha
authors.forename: A
authors.initials: A
authors.lastname: Banzato
authors.forename: E
authors.initials: E
authors.lastname: Bison
authors.forename: G
authors.initials: G
authors.lastname: Denas
authors.forename: A
authors.initials: A
authors.lastname: Bracco
authors.forename: S
authors.initials: S
authors.lastname: Padayattil Jose
mesh_terms: D000328:Adult; D017153:Antibodies, Anticardiolipin / Q000276:immunology; D017152:Antibodies, Antiphospholipid / Q000097:blood* / Q000276:immunology; D016736:Antiphospholipid Syndrome / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D016682:Lupus Coagulation Inhibitor / Q000097:blood* / Q000276:immunology; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012306:Risk; D013927:Thrombosis / Q000097:blood*; D013997:Time Factors; D053482:beta 2-Glycoprotein I / Q000737:chemistry*
chemical_list: D017153:Antibodies, Anticardiolipin; D017152:Antibodies, Antiphospholipid; D016682:Lupus Coagulation Inhibitor; D053482:beta 2-Glycoprotein I
keywords: cardiolipin; glycoprotein I; lupus anticoagulant; phospholipid; thrombosis; β2