Certain medications and previous illnesses may disqualify donors, however these can be verified by contacting the blood center in advance. A whole blood donor can give blood every eight weeks. The pint donated is approximately one tenth of the body's volume which will return to normal within several hours after the donation. The apheresis donation process is also virtually painless, however, it takes approximately two hours to complete. During this special type of donation, platelets are collected.
Platelets help the blood to clot.
Apheresis donors complete the same mini physical and medical history interview process as whole blood donors. During the apheresis donation, blood is drawn from a vein in the donor's arm. Instead of being collected in a bag, the blood is run through sterile tubing and into a centrifuge inside a blood-cell separator. The centrifuge spins the blood so that the platelets are separated from the rest of the blood. The platelets are collected in a bag and the remainder of the blood is returned to the donor.