Abstract:Abstract : Objective To investigate the effects of gender, age, and ABO blood type on the detection of von W ilebrand factor ( vWF)antigen (vWF: Ag) and activity (vWF: Ac) in children, and establish the reference intervals of vWF: Ag and vWF: Ac for children.Methods 857 children who had no clinical manifestation of bleeding or coagulation and had normal results of routine coagulation tests were selected randomly from our hospital, and their plasma vWF: Ag and vWF: Ac and ABO blood type were detected. Results The levels of vWF: Ag and vWF: Ac in the low age group (≤6 years old ) were significantly lower than that in the high age group (>6 and≤18 years old, P<0.05). The levels of vWF: Ag and vWF: Ac in children with type 0 blood were significantly lower than that with non-O blood type in different age groups ( P<0.001). For children aged≤6 years , the reference intervals of vWF: Ag and vWF: Ac in the type 0 blood group were 44.4%-130.6% and 43.0% -194.7% , respectively, and those in the non-O blood type group were 66.3%-190.4% and 71.3%-282.3%, respectively. For children aged >6 and≤18 years, the reference intervals of vWF: Ag and vWF: Ac in the type 0 blood group were 50.4%-145.4% and 51.7%-221 .4% , respectively, and those in the non-O blood type were 75. 4%-195.6% and 84.0% -296.5%, respectively. Conclusion The levels of plasma vWF: Ag and vWF: Ac in children are afected by age and ABO blood type. Laboratories should actively establish the specifie reference intervals of vWF in children,which will be helpful for compre-hensively assessing the risk of bleeding and thrombosis in children.