Increasing blood availability by changing donation patterns.

Abstract

BACKGROUND: There is a declining margin between US blood collections and transfusions. Donation patterns were examined to characterize returning first-time donors and predict the impact on blood availability of decreasing the number of nonreturning donors. STUDY DESIGN AND METHODS: First-time donors giving between 1991 and 1994 were followed for 3 to 6 years. The impact of decreasing the number of nonreturning donors in a 12-month period was projected using the Poisson distribution to model the donation patterns of 539,063 donors who gave in 1995. Repeat donors were classified as "returning first-time" (gave a first-time donation within 12 months of their index donation), "established" (gave a repeat donation), and "inactive" (didn't donate in the 12 months before their index donation). RESULTS: A total of 49 percent of first-time donors did not return within 6 years. Returning first-time donors tended to be US born, white, and had more than a high school education. In 1995, 30 percent of donors were first time, 31 percent were established, 7 percent were returning first time, and 32 percent were inactive, giving 1.5, 2.4, 1.9, and 1.7 donations in 12 months, respectively. Reducing nonreturning donors by 5 percent could increase blood collections by 2.7 percent. Similarly, 15 or 25 percent reductions in nonreturns could increase collections by 8.6 or 16.0 percent, respectively. CONCLUSIONS: Most donors are not giving near the donation limit. A substantial increase in donations could be achieved by a relatively small decrease in donor nonreturn. Research is needed to understand why approximately half of first-time donors donate only once.