Early intraoperative blood collection does not affect complete blood counts, von Willebrand factor or factor VIII levels in normal children.

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.

Observations: 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.