The potential impact of selective donor deferrals based on estimated blood volume on vasovagal reactions and donor deferral rates

To increase the number of blood components available for distribution, blood collection agencies have expanded the use of donor incentives to attract new donors, encouraged current or lapsed donors to give more frequently, increased the collection of multiple components by apheresis from individual donors, aggressively pursued donation by high school and college donors, and supported state legislation to decrease the minimum age for a blood donation to 16 years of age.1 Of concern, however, is whether any of these steps, particularly collecting from young donors, results in increased risk of adverse events for the individual donor. Blood collection facilities have the dual obligation to make the donation process as safe as possible for the donor and to provide an adequate blood supply to the community; consequently, they should design measures to minimize risk to donors as they strive to increase the number of blood components available for transfusion.2,3 Blood donation is generally well tolerated by most individuals; however, some people will experience adverse events after the collection of whole blood by manual methods. The most common complications are small hematomas and prefaint (presyncope) reactions, occurring in up to 16 and 5% of donors, respectively.4 Potentially more significant adverse events range from vasovagal syncope (loss of consciousness) with occasional injuries from falling or accidents, phlebotomy-related reactions such as hematomas, nerve irritation/injuries, arterial punctures, phlebitis, and thrombosis and skin infections to rare systemic reactions, allergy/anaphylaxis, and myocardial infarction. A voluntary blood donation has not been causally implicated in a donor’s death, based on reports to the US Food and Drug Administration.5 Prefaint reactions and loss of consciousness after donation are of particular concern, because they may lead to falls, injuries, and accidents and reduce the likelihood that a donor will return to donate again.1,6 Many studies have highlighted young age, first-time donation status, female sex, low weight, and Caucasian race as important risk factors for reactions, and high school students are at particular risk.1,3,7,8 Eder and colleagues1 reported that donors aged 16 and 17 years have higher rates of vasovagal reactions than older donors and that high school–age donors experiencing adverse reactions are less likely to donate blood in the future. Younger donors also had significantly higher rates of donor reactions needing additional medical care than adult donors (5.8 reactions/ 10,000 collections for donors age 16-17 years vs. 2.9 reactions/10,000 collections for donors aged ≥ 20 years). Wiltbank and coworkers3 also reported the risk factors for vasovagal reactions in donors 17 years or older and showed that estimated blood volume (EBV) and body mass index are risk factors for mild (pallor, sweating, anxiety, or reactions lasting 30 min) donor reactions among whole blood donors. Donors with an EBV of less than 3.5 L had an odds ratio (OR) for prefaint and faint reactions of 2.88 (95% confidence interval [CI], 2.57-3.23).3 A low body mass index (<18.5) was also associated with a high risk for prefaint and faint reactions (OR, 2.51; 95% CI, 1.99-3.15). These authors noted that donors with an EBV of less than 3.5 L are at risk of the loss of more than 15% of their blood volume with the donation of a standard unit of blood under current AABB Standards that limit blood loss to 10.5 mL/kg (525 mL from a 50-kg [110-lb] donor). This study led the authors to implement additional donor eligibility criteria requiring that male and female donors ages 16 to 22 years have a total blood volume of 3.5 L or more.9 With this background, we conducted a study of the relationship of risk factors such as weight, height, and EBV, with prefaint and systemic vasovagal reactions (SVRs) among donors of allogeneic whole blood as young as 16 years old, in two American Red Cross (ARC) regions participating in the NIH-sponsored Retrovirus Epidemiology Donor Study-II (REDS-II). The study focused on the potential benefit and impact of implementing donor restrictions based on EBV.