BACKGROUND: Collection, processing, and transfusion of blood and blood components in the United States in 2001 were measured and compared with prior years.

STUDY DESIGN AND METHODS: The survey was completed by 1443 blood centers and hospitals. Statistical procedures were used to verify the representativeness of the sample and to estimate national totals.

RESULTS: The total US blood supply in 2001 was 15,320,000 units (before testing), 10.4 percent greater than in 1999. It included 14,259,000 allogeneic units, 619,000 autologous units, and 273,000 red cell (RBC) units collected by apheresis. Transfusion of whole blood (WB) and RBCs increased by 12.2 percent to 13,898,000 units. Platelet (PLT) transfusions totaled 10,196,000 units, an increase of 12.6 percent in comparison with 1999. The use of single‐donor apheresis PLTs increased by 26.0 percent to 7,582,000 PLT concentrate equivalent units. The use of PLTs from WB (PLT concentrates) continued a downtrend, declining 13.9 percent to 2,614,000.

CONCLUSIONS: The margin between transfusion demand and the total allogeneic supply in 2001 was 1,162,000 units, 7.9 percent of supply. By comparison, the 1999 margin was 9.1 percent. The rate of blood collection per 1,000 donor‐eligible population in 2001 was 8.9 percent higher than in 1999, due largely to additional donations following the September terrorist attacks. During the same period, however, the rate of transfusion per 1,000 total US population increased by 9.9 percent to 50.0 units, the highest in 15 years of measurement. The steady increase in demand continues to challenge the US blood community.