title: Applying a direct aPTT ratio (PlatelinLS/ActinFS) permits to identify rapidly and reliably a bleeding-related factor deficiency or a lupus anticoagulant sequential to an isolated prolongation of aPTT in paediatric pre-operative screening.
abstract: OBJECTIVE
  An isolated prolongation of activated partial thromboplastin time (aPTT) found in paediatric pre-operative screening could be due to bleeding or non-bleeding aetiologies. The aim of our study was to evaluate clinical benefits of an additional ActinFS and/or a mixing aPTT study to identify a bleeding-related factor deficiency (BRFD).
  
  
  METHODS
  Over a 4-yr period, isolated prolongation of aPTT with PlatelinLS was detected in 308 paediatric patients and confirmed in 161 cases by a 2nd sample. ActinFS, a mixing study, FVIII, FIX, FXI, FXII and lupus anticoagulant (LA) were performed. Three different aPTT ratios between PlatelinLS and ActinFS were analysed.
  
  
  RESULTS
  We found 17 BRFD, 31 FXII deficiencies and 64 positive LA. A prolonged ActinFS had a significant association with BRFD (P < 0.0001) while a corrected mixing study did not. The direct aPTT ratio had a significant relationship with positive LA (P < 0.05), and with BRFD (P < 0.0001). Using this ratio, the sensitivity of BRFD's and LA's detection could be increased, respectively, to 82% from 59% using ActinFS alone, and to 86% from 55% using mixing study.
  
  
  CONCLUSIONS
  Applying this direct aPTT ratio allows to quickly and reliably identify both BRFD and LA sequential to an isolated prolongation of aPTT.
authors.affiliation: Laboratory of Haematology, iris-Lab, Institut Jules Bordet and Saint Pierre University Hospital, Université Libre de Bruxelles, Brussels, Belgium.
authors.forename: Rong
authors.initials: R
authors.lastname: Li
authors.affiliation: Laboratory of Haematology, iris-Lab, Institut Jules Bordet and Saint Pierre University Hospital, Université Libre de Bruxelles, Brussels, Belgium.
authors.forename: Caroline
authors.initials: C
authors.lastname: Swaelens
authors.affiliation: Laboratory of Haematology, iris-Lab, Institut Jules Bordet and Saint Pierre University Hospital, Université Libre de Bruxelles, Brussels, Belgium.
authors.forename: Francine
authors.initials: F
authors.lastname: Vandermijnsbrugge
authors.affiliation: Laboratory of Haematology, iris-Lab, Institut Jules Bordet and Saint Pierre University Hospital, Université Libre de Bruxelles, Brussels, Belgium.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Cantinieaux
mesh_terms: D000293:Adolescent; D001777:Blood Coagulation; D001780:Blood Coagulation Tests; D002648:Child; D002675:Child, Preschool; D020147:Coagulation Protein Disorders / Q000175:diagnosis* / Q000601:surgery; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D016682:Lupus Coagulation Inhibitor / Q000097:blood*; D008297:Male; D010314:Partial Thromboplastin Time; D011300:Preoperative Care / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D016682:Lupus Coagulation Inhibitor
keywords: ActinFS; factor deficiency; mixing study; pre-operative screening; prolonged activated partial thromboplastin time