Plateletphaeresis



*Plateletphaeresis*

Plateletphaeresis is the process of extracting platelets from the blood. This can be done in the laboratory but can also be done in the donation area.

Plateletphaeresis in the laboratory

Platelets can be collected in the laboratory from freshly collected (whole) blood. It takes 5-8 bags of blood of the same group to make one unit or a bag of platelets. These are known as pooled platelets.

Plateletphaeresis in the donation area

Platelets can be collected directly from a donor by means of a special machine. This machine draws blood in a special reservoir called centrifuge; separate the platelets from the rest of the blood; the platelets are saved in a special plastic bag; while the rest of the blood is returned to the donor. This is one cycle. To make one unit of platelets the machine makes 6-8 cycles of about 10 minutes each. This unit of platelet is called single donor platelets, as the name implies, platelets from just one person.

What are the indications of pooled and single donor platelets?

First we need to give some explanation. Those patients suffering from leukaemia and other similar cancers of the blood have a severe drop in platelets (platelet count). The platelet count drops down so much that the patients starts to bleed from the gums, under the skin and in the urine. This might be fatal. Additionally, these patients suffering from blood cancers receive special treatment called chemotherapy. Chemotherapy drops down the number of white blood cells. This makes the patient highly vulnerable to infection as white blood cells are responsible to combat infection. Lets us further explain blood transfusion. In any two bloods (recipient and donor), although of the same blood group, it is highly probable that a variety of substances in each blood are not exactly similar. Therefore in every transfusion there is always the formation of antibodies in the recipient's blood to neutralize the foreign substances of the donor. Consequently, a patient who had many blood transfusions would have a high variety of different antibodies. These antibodies in the patient's blood might ultimately start to reject every foreign blood even of the same blood group. In the light of the above brief explanation, a patient receiving pooled platelets would be receiving substances from many different persons. Patients who are good candidates for a bone marrow transplant, or any other transplant, are not transfused pooled platelets but single donor platelets, to reduce the variety of antibodies that might reject the transplanted organ.

Platelet Machine Pooled platelets are also perceived to raise the risk of inducing an infection although this issue is being argued. However, some literature points out that the high quality in blood processing (screening) makes pooled platelets safe as single donor platelets.

Who can donate platelets?

Platelet donors are selected from the pool of blood donors. A donor who has suitable veins and has donated for some times are asked to donate platelets. Men are usually the best candidates but woman can also be platelet donors as long as the veins are perceived suitable. The necessity to have good veins is simple. As the machine draws and returns a considerable amount of blood, it is necessary that the vein must be of a certain caliber. First timers blood donors are not allowed to donate platelets.Platelet donors very dedicated people since the procedure is longer. Platelet donors are called when needed because platelets cannot be kept in reserve more than 5 days.
Donors are usually asked to donate platelets for the day but sometimes they are also asked to come immediately. If the donor cannot make it then the nurses ask somebody else.

How safe is platelet donation?

The procedure of platelet donation is a very common one and is performed nearly every day. The complications are negligible because the machine is equipped with very sensitive air detectors and monitors. The platelet extraction set is disposable. No significant complications were ever reported yet.