Researchers interviewed 2,730 whole blood donors at high school community blood drives in Kansas City to evaluate donor reactions. Donors were asked if they feared having blood drawn.
Phlebotomists also recorded vasovagal reactions and blood draw times in addition to other donor variables including sex, weight, pulse, and donation status. Researchers found that both fear and blood draw time increased the odds of a vasovagal reaction by three-fold at each draw time examined, and that the effect was additive. Donors who were fearful and had draw times longer than 10 minutes had the highest rate of vasovagal reactions (31.2%) compared to donors who were the least fearful of blood draws and had blood draw times less than 6 minutes (5.0%). Fear was the best predictor of vasovagal reactions. This finding suggests that fearful blood donors should receive additional support and observation during blood draws.