These intervals are mandated to give the donor’s body time to replenish their red cells and iron stores or in the case of plasma, to allow time for antibodies that protect the donor from bacteria and viruses to be restored.
Another layer of donor safety the FDA regulates is the total donation/loss permitted in a rolling 12-month period of both red blood cells and plasma.
This protective policy can create donor deferral periods among frequent donors who choose to donate a combination of red blood cells, platelets, and plasma in the fluid 365-day eligibility interval.
Red Blood Cells
The total allowable loss of red blood cells that can be donated is a factor of the donor’s overall blood volume, which is calculated by their height, weight, and hemoglobin level.
So, the allowable amount that can be given during a 365-day period can vary for each donor. Another factor that contributes to red blood cell loss for all donors is the amount of blood drawn into test tubes to be used for blood testing in our laboratories. Although this is a small amount, every drop counts and is measured.
Each time a platelet donor shares this special gift, there can be a residual loss of 20-30 ml of red blood cells which remain in the individual collection set, which includes sterile tubing and satellite bags. This is also calculated. Although double-needle platelet procedure donors experience less of this small loss, it still all adds up, especially for frequent donors. alt text
During platelet donations, there is always some plasma collected to mix back with the platelets after donation.
This mix of components is made to keep the platelets suspended until transfusion and provide the clotting factors that help them stick together.
At the same time, during the donation of platelets, many donors also give a concurrent plasma as often as every 28 days to provide an additional gift to patients.
The amount of plasma collected from both of these donations occurring at the same time is calculated and cumulatively added to the donor’s records in our computer system.
The maximum volume of plasma that can be given in a rolling 12-month period has a demarcation divide of 175 pounds. If the donor weighs below this amount, the cut-off is at 12 liters total. If the donor weighs more than 175 pounds, they can give up to 14.4 liters. If you have not reached these limits when you come to donate platelets, you can still donate that day.
However, if you exceed the FDA guidelines during that donation, you may find yourself with a longer interval period than you normally would, until the rolling 365 day period resets.
OneBlood frequent donors who periodically donate whole blood between platelet donations sometimes question why they are not able to make another whole blood donation when they have only given 5 times in the rolling 12 months. It is because of the blood drawn each time for testing and the residual blood in the platelet kits after their donations. The aggregate puts donors over the allowable limit for volume and/or overall frequency when combined with their platelet donations.
Sometimes donors who faithfully only give platelets find themselves deferred having given less than 24 times in a rolling 12 month period. When they ask why they discover it was their donations of concurrent plasma that put them over the total allowable volume during that time period.
Everything we do at OneBlood begins with volunteer donors. We recognize and affirm that frequent donors are not only the safest donors but the backbone of our blood supply.
At the same time, based not only on FDA policy but on our care for their good health, we sometimes need to tell them to take a well-deserved rest. Then, when they are eligible we welcome them back to share more of their best!