title: Early intraoperative blood collection does not affect complete blood counts, von Willebrand factor or factor VIII levels in normal children.
abstract: BACKGROUND
  Obtaining blood from children for research studies can be difficult, particularly for controls. One solution is to obtain samples during elective surgery; however, consideration must be given to the potential effects of the timing of phlebotomy.
  
  
  METHODS
  Ten children were recruited and phlebotomy was carried out during a preoperative clinic visit and intraoperatively immediately after the induction of anesthesia but before the start of surgery. CBCs, VWF, and FVIII levels were measured at both time points and no significant differences were seen.
  
  
  CONCLUSIONS
  This negative result may be beneficial to pediatric research by suggesting that early intraoperative blood collection for controls does not affect the results.
authors.affiliation: Department of Medicine, Queen's University, Kingston, Canada.
authors.forename: Hanni
authors.initials: H
authors.lastname: Darwish
authors.forename: Gillianne
authors.initials: G
authors.lastname: Mundell
authors.forename: Dale
authors.initials: D
authors.lastname: Engen
authors.forename: David
authors.initials: D
authors.lastname: Lillicrap
authors.forename: Mariana
authors.initials: M
authors.lastname: Silva
authors.forename: Paula
authors.initials: P
authors.lastname: James
mesh_terms: D000293:Adolescent; D001772:Blood Cell Count; D002648:Child; D002675:Child, Preschool; D005169:Factor VIII / Q000032:analysis*; D005260:Female; D006801:Humans; D008297:Male; D018962:Phlebotomy; D012016:Reference Values; D014841:von Willebrand Factor / Q000032:analysis*
chemical_list: D014841:von Willebrand Factor; D005169:Factor VIII