How much blood can one donate at a time?

Current FDA guidelines allow a maximum of 10.5 ml/kilogram body weight of whole blood to be collected every eight weeks. The majority of blood collection facilities use 500 ml whole blood bags, with an additional 50 ml (10%) allowed to be drawn for mandated screening tests.

Double red cell donation by apheresis technology may collect 500-550 ml of red cells at a single donation IF the donor meets body mass and hematocrit eligibility criteria. Double red cell donors must wait 112 days before their next blood donation attempt (any type).