The process for donating blood is a safe, relatively painless one, which takes an average of about an hour depending on the donor. Once a donor arrives at the donation site, he is screened through a series of simple tests and questionnaires to determine eligibility. When the person's ability to donate blood has been established, he is led to a table to sit in a reclining position, while the phlebotomist prepares and inserts the needle to begin donation. When one unit of blood has been drawn, the donor is served juice and other refreshments, and remains seated for a short time before leaving.
Donating blood can be a rewarding experience that can end up saving the life of an injured or sick person in need of blood. Men and women can give blood regardless of their blood type, but the donor must be free of certain diseases, in order to keep these from spreading. Although it is very rare, it is not unheard-of for disease to be passed by a blood transfusion, and great care is taken to avoid such occurrences, insofar as this is possible. There are also age and weight requirements, to ensure that the process will be safe for the donor's body.
The first line of defense against the spread of disease is the donor screening process. Prior to donating blood, every candidate is given a lengthy questionnaire. Here, the donor is asked about his travels, sexual and medical history, and other things which could possibly preclude him from donating blood. For example, if a person has traveled to an area of the world where it is possible to contract malaria, he is required to wait a year before donating blood, even if he did not contract the disease.
After this part of the screening, the donor's blood pressure and pulse are taken, and a small amount of blood is tested for anemia. Specifically, the test reads a person's hematocrit level, which is the percentage of the total blood volume that is made up of red blood cells, those which carry iron and oxygen. A lowered hematocrit level may keep a person from donating blood that day, but it is generally not a cause for concern.
At this point, if the candidate meets all the requirements, he is led to a separate area to begin the donation itself. A hollow needle is inserted into a vein on the inside of the donor's elbow, after the area has been sterilized. It is attached to a narrow tube through which blood flows into a bag to be collected. Generally, one unit of blood is collected, approximately equal to one pint (0.45 liter).
After the blood is drawn, the donor sits up and stands up slowly, to make sure he is steady on his feet, since donating blood can make a person lightheaded. As an extra precaution against the spread of disease, the donor is given a card with a phone number and a reference number which corresponds to his particular blood. If, at any time after the donation, the person decides that it is not safe for his blood to be used, he can call the number and the blood will be discarded.