Plasma products can be used to help prevent health problems occurring in conditions such as Rhesus disease, and to prevent bleeding in patients who suffer with haemophilia (a lack of clotting substances).
Plasma can also be given as a transfusion when a patient has lost a lot of blood.
Plasma transfusions
A plasma transfusion is where whole blood is taken from one person, known as a donor, and the plasma is separated from the red cells and then frozen until it is needed, when it is thawed and given to another person.
For example, a patient may be given a plasma transfusion if they are bleeding after a serious accident or following major surgery where clotting factors need replacing as well as red blood cells.
Before someone is able to donate blood for the production of plasma for transfusion, they have to comply with a strict set of guidelines about their medical, travel and sexual history. This ensures that their blood is safe to be transfused. As with whole blood, plasma is always checked for viruses to make sure it is safe to use.
Plasma transfused to patients who were born after January 1 1996 comes from donors outside the UK. It has been treated with a chemical called methylene blue, which is an additional step that was introduced to make plasma safer.
See the Health A-Z topic about Blood transfusions for more information about the process.
Plasma products made by fractionation
Many of the components that are found in plasma can be refined and extracted so they can be used to treat specific problems.
Plasma donations are pooled and then subjected to a number of different heat and chemical treatments, before the various proteins are separated out in a complex process that is known as fractionation. Fractionation can take up to five days.
All blood donations that are used to make plasma pools for fractionation have to be checked for viruses to make sure they are safe to use. In addition, the pooled plasma is carefully filtered and "cleaned" using heat, detergents and solvents to remove any viruses that may be present.
After the fractionation process has been completed, the plasma products are either freeze-dried as a powder for reconstitution before use or kept as a liquid. They are then bottled ready for distribution to clinics, surgeries and hospitals.
Some patients, such as those with haemophilia, have their own supply of plasma products so they are able to treat themselves at home.
There are hundreds of plasma products that can be created, but the three main ones are:
- human albumin solution
- clotting (coagulation) factors
- normal human immunoglobulin
See Plasma products – Introduction for more information about these three plasma products.
Plasma exchange
Plasma exchange, also known as plasmapheresis, is a procedure where a special machine (see below) is used to separate plasma from the other components of a patient’s blood.
During the procedure, the plasma is removed and replaced with a substitute (usually human albumin solution) and the red cells, white cells and platelets are returned to the patient.
Plasma exchange is often used to treat a number of rare blood conditions. These are briefly outlined below.
Thrombotic thrombocytopenic purpura
Thrombotic thrombocytopenic purpura is a rare disorder of the blood coagulation system, where microscopic blood clots damage organs and red blood cells.
Plasma exchange removes the antibody that is responsible for causing the condition, as well as replenishing blood levels of a vital enzyme using fresh frozen plasma.
Multiple myeloma and Waldenström's macroglobulinaemia
Multiple myeloma and Waldenström's macroglobulinaemia are both rare types of bone marrow cancer where abnormal bone marrow cells create large amounts of a protein called a paraprotein (immunoglobulin).
If the protein levels in the blood become too high, the blood can thicken, which is known as hyperviscosity. The symptoms of hyperviscosity include:
- headaches
- fatigue (tiredness)
- blurred vision
Plasma exchange reduces the amount of abnormal protein in the blood, which helps to relieve the symptoms. However, the process does not prevent the production of immunoglobulin. Other treatments, such as chemotherapy, may be required to achieve this.
Plasma exchange procedure
During plasma exchange, a machine called a cell separator will be used to separate the plasma from your blood. A needle will be inserted into a vein in your arm, and blood taken from your vein will be passed through the cell separator.
The plasma will be separated from the rest of your blood and a plasma substitute added, before the blood is returned through a needle in a vein in your other arm.
Plasma exchange takes about two hours to perform. During the process, only a small amount of blood (less than 100ml) will be outside your body at any one time. This is because the blood being extracted will be returned at the same rate.
The amount of plasma that is exchanged will depend on factors such as:
- your height
- your weight
- how thick your blood is
The number of plasma exchanges that you will need will depend on your symptoms, how much protein there is in your blood and how well you are responding to your other treatments.
Side effects
Faintness and lightheadedness are both possible side effects of a plasma exchange. If you feel faint or lightheaded you should tell the healthcare professional who is treating you. The symptoms can usually be effectively treated by changing to a lying down position. Ensuring that you have something to eat on the day of the procedure will also help you to avoid feeling faint and lightheaded.
During a plasma exchange, you may also experience numbness or a tingling sensation around your nose and mouth and in your fingers. This is caused by a substance called citrate, which is added to your blood while it is outside your body to prevent it clotting (thickening). The citrate may affect the levels of calcium in your blood.
Let the healthcare professional who is treating you know if you experience numbness or tingling sensations. They may stop the plasma exchange for a few minutes until your body adjusts to the increased citrate levels in your blood, or they may increase the level of calcium in your blood by giving you a milky drink. Eating foods that contain calcium, such as dairy products, before you have the procedure may also help.
