Vaccines, Blood & BiologicsKeeping the United States blood supply the world’s safest is the ultimate responsibility of the nation’s more than 3,000 blood establishments, which collect and process 14 million units of whole blood donated by volunteers each year. The Food and Drug Administration, however, has the vital role of ensuring that the 3.5 million patients who receive a blood transfusion in a year are protected by five layers of overlapping safeguards. This FDA blood-safety system includes the following measures: