1. Erythrocytapheresis

2. Erythrocytapheresis
Erythrocytapheresis is an apheresis procedure by which erythrocyte (red blood cells) are separated from whole blood.
It is an blood separation method whereby whole blood is extracted from a donor, the red blood cells are separated, and the remaining blood is returned to circulation.

3. Red blood cells is present in the highest percentage of all blood cell components in the solid portion of blood. Therefore, since erythrocytes have the highest specific weight in comparison to other solids in blood, they can easily be separated using centrifugation.
Normal RBCs: 4-6 * 10^12/L

4. Whole blood is spun down in a spinning bowl centrifuge and the bottom layer, concentrated with erythrocytes, sediments to the bottom. These are separated and the rest of the blood can be retransfused.
Whole blood enters the centrifuge (1) and separates into plasma (2), leukocytes (3), and erythrocytes (4). Selected components are then drawn off (5).

5. Each year, about 7,000 units of red blood cells are needed in the National Institutes of Health (NIH) Clinical Center (CC) to treat patients undergoing cancer therapy, organ and tissue transplants, and other diseases that require blood transfusions.

6. If you'd like to donate but can't seem to find the time, now there is a new donation option at the NIH Blood Bank called Double Red Cell Apheresis (DRCA).
This procedure will let you give 2 units of red cells in one visit to the Blood Bank. Although the procedure takes slightly longer than a single-unit donation, it accomplishes twice as much.
Double red cell donation will save you time spent traveling, parking, and undergoing medical screening on two separate different occasions, because one visit accomplishes two donations.

7. What Is DRCA?
DRCA is a procedure that allows a donor to give 2 units of red cells at the same time. This is done by a procedure called "apheresis," which separates whole blood into component parts such as red blood cells, platelets, and plasma.
To remove red cells, a needle is placed in your arm, and the blood flows into a sterile, disposable plastic kit installed in a machine designed specifically for this purpose.

8. As blood enters the machine, the bowl is spinning at high speed
As blood enters the machine, the bowl is spinning at high speed. This causes the components of the blood to separate so that the red blood cells can be siphoned into a blood bag.
Plasma and other parts of the blood are then returned to you through the same needle. The process is repeated to collect 2 units of red blood cells.

9. Is DRCA Safe?
Absolutely. The machine and the procedure have been evaluated and approved by the Food and Drug Administration (FDA), and all plastics and needles coming into contact with you are used once and discarded.
At no time during the procedure is the blood being returned to you detached from the needle in your arm, so there is no risk of returning the wrong blood to you.

10. What Are The Donor Requirements?
Because you will be losing more red blood cells than usual during this procedure, donor criteria differ from those for whole blood donation:
Men
Minimum weight pounds ≈ 59 kg
Minimum height - 5'1“Inches  ≈ 155 cm
Women
Minimum weight pounds ≈ 68 kg
Minimum height - 5'5“Inches  ≈ 165 cm

11. Donors must have a slightly higher red cell count, specifically, a fingerstick hemoglobin level of at least 13.3 gm/dL.
To assure that you do not become anemic, the interval between DRCA and subsequent blood donation is 4 months.

12. How Long Does The Procedure Take?
The time required to remove 2 units of red cells is about 45 minutes. Because you'll be with us longer, there will be time to watch TV, read, or just chat with staff and other donors. Every effort will be made to make the experience relaxing and enjoyable.

13. Applications
Therapeutic erythrocytopheresis is commonly used to remove red blood cells in patients experiencing sickle cell crisis.
The affected erythrocytes are removed while the rest of the blood is retransfused. This blood separation is also used in patients with severe malaria.

14. Sickle-cell disease
Sickle-cell disease (SCD), or sickle-cell anaemia (or anemia, SCA) or drepanocytosis, is an genetic blood disorder, characterized by red blood cells that assume an abnormal, rigid, sickle shape.
Sickling decreases the cells' flexibility and results in a risk of various complications. The sickling occurs because of a mutation in the hemoglobin gene, causing the glutamic acid (hydrophilic amino acid) to be replaced with the valine (hydrophobic amino acid) at the sixth position.

15. Malaria
Malaria is an infectious disease of humans and other animals caused by plasmodium.
The disease results from the multiplication of Plasmodium parasites within red blood cells, causing symptoms that typically include fever and headache, in severe cases progressing to coma or death. It is widespread in tropical and subtropical regions, including much of Africa, Asia, and the Americas.

16. After removal of the infected cells, the patient can then be transfused with a dose of normal red blood cells. This process is commonly done using automated red blood cell collection which involves the removal of two units of red blood cells (double red).
you are eligible to donate only every 16 weeks (4 moths).