Types of Donations

The most common type of donation performed in blood collection centres is whole blood donation. Whole blood as present in the vein is collected from the donor and is later processed and separated into different products in laboratories. However there are other types of different donations that can be performed. Only particular donors can donate specific blood products and the NBTS selects these from regular donors.

Aphaeresis

The term aphaeresis comes from Greek meaning to extract. The process of aphaeresis involves the extraction of a component of blood by means of a special machine. There are two main types of aphaeresis:

Plasmaphaeresis is the extraction of plasma from whole blood. This used to be done in the donation area and used to be a common procedure. However, at present, every bag of whole blood is separated in the laboratory (fractionation) into three separate units, i) plasma ii) red blood cells concentrate and iii) the buffy coat (white blood cells and platelets in some plasma). The buffy coat and the plasma may be further separated in the laboratories to extract more products. Refer to the laboratories section for further details.

Plasma transfusion may be necessary to replace acute blood loss such as in severe burns. As plasma contains the clotting factors, it is also indicated to correct or relieve symptoms of many bleeding disorders.

Plasma exchange

Plasmaphaeresis can also be therapeutic, that is, the plasma is extracted and replaced usually with human albumin (or other substitute) to help the condition of the patient. Certain diseases require that plasma is extracted to remove certain toxins (poisons) in the plasma. While the plasma is being removed it is replace by albumin or other fluids simultaneously. Examples of diseases that require plasma exchange are Guillain Barre Disease and Myasthenia Gravis.

This new procedure involves the extraction of only red cells from the donor, while the other components are transmitted back to the donor via a special machine. Choosen candidates might even give 2 units of red cell concentrate during one donation.

Leukophaeresis

Leukophaeresis is a therapeutic procedure (to help the condition of the patient) where white blood cells are extracted from a person. This procedure is done on patients suffering from a particular blood disease like leukemia, where it is necessary to remove extra white blood cells. In certain diseases of the blood, the white blood cells rise up to a very high abnormal number, causing thrombosis (blockage) in the veins and arteries in various organs causing complications. This type of aphaeresis, granulocyte/leukophaeresis is always therapeutic.

Plateletphaeresis

The most important type of aphaeresis is the extraction of platelets from blood which is known as plateletphaeresis. For further details please go here.