title: [Detection of hemophilia A carrier by FⅧ:C/vWFAg ratio].
abstract: OBJECTIVE
  To determine the cut-off value for coagulation factor Ⅷ activity (FⅧ:C) to von Willebrand factor antigen (vWFAg) ratio which can classify obligatory carriers of hemophilia A and normal females, and assess its feasibility to diagnose suspected carriers in affected families through comparison with the method of gene diagnosis.
  
  
  METHODS
  FⅧ:C assay was carried out by a one-stage method in both obligatory carriers and normal females. vWF antigen was measured with ELISA assay. The FⅧ:C/vWF ratio was calculated. Statistic analysis was carried out to determine the cut-off value which can classify the two groups. The ratio was then used to diagnose suspected carriers from families affected with hemophilia A. The results were compared with that by long distance polymerase chain reaction, genetic linkage analysis and/or direct sequencing.
  
  
  RESULTS
  The FⅧ:C/vWFAg value for 90.6% of obligatory carriers was under 0.82. Should 0.82 be selected as the cut-off value to diagnose the 42 suspected carriers, most of them can be readily diagnosed. The results were all in agreement with that of genetic analysis.
  
  
  CONCLUSIONS
  Cut-off value of FⅧ:C/vWFAg may be used for initial diagnose of the suspected carriers from families affected with hemophilia A. The method is quite convenient and reliable.
authors: Blood Center of Shandong Province, Jinan, Shandong 250014, P.R. China. sdxyzxljl@126.com.
authors: Li
authors: L
authors: An
authors: Jin-ling
authors: JL
authors: Liu
authors: Xin-sheng
authors: XS
authors: Zhang
authors: Yan
authors: Y
authors: Cheng
authors: Yun-hai
authors: YH
authors: Fang
mesh_terms: D001780:Blood Coagulation Tests / Q000379:methods; D005169:Factor VIII / Q000235:genetics*; D005260:Female; D008040:Genetic Linkage; D006467:Hemophilia A / Q000175:diagnosis* / Q000235:genetics*; D006801:Humans; D008297:Male; D014841:von Willebrand Factor / Q000235:genetics*
chemical_list: D014841:von Willebrand Factor; D005169:Factor VIII