What is Plasma?
Plasma is the fluid component of blood in which red blood cells, white blood cells and platelets are suspended. Almost 55% of blood is made up of plasma making it the major component by weight in blood. All these 4 major components of blood can be easily separated in a laboratory using special machines and processes. In recent times, plasma is playing a major role in treating serious health conditions. It is also an important component in cosmetic procedures that use Platelet-rich-plasma (PRP).
What does Plasma contain?
Plasma when separated out is light-yellow-colored. The red color to blood comes from red-blood-cells. Plasma contains:
- Water: 92% of the weight of plasma is water
Around 7% by weight is made of the following components
- Plasma proteins: Immunoglobulins make up nearly 20% of all the proteins in blood plasma. They are produced by the body’s immune system and help fight infections caused by bacteria, viruses, fungi and parasites. Other proteins in blood plasma include globulin and albumin which help maintain or control blood pressure in the body.
- Coagulants: Also called Clotting factors, these help the blood clot when there is injury or hemorrhage thereby stopping blood loss. The most common coagulant is fibrinogen. These coagulants are the primary component in any blood clot.
The remaining 1% by weight is made of electrolytes, sugars, fats, hormones and vitamins.
- Electrolytes: These include salts of calcium, sodium and potassium along with chloride and bicarbonate. Electrolytes play different roles in different parts of the body. In the blood plasma, they help maintain proper pH levels.
Roles and Functions of Plasma
- Coagulation: Along with Fibrinogen, Factor X and thrombin are other coagulants present in plasma that help the clotting process. Without coagulation, a person would bleed to death.
- Immunity: Immunoglobulin G, M, and A as well as antibodies such as anti-A and anti-B are all disease-fighting proteins. That is, by fighting pathogens, they help maintain the immunity levels in the body.
- Maintaining BP and blood-volume: Albumin and Fibrinogen are two proteins present in blood plasma. As discussed above, fibrinogen helps clot blood and prevent blood-less thereby ensuring adequate blood volume. Albumin on the other hand is responsible for maintaining what is called oncotic pressure of the blood. That is, it prevents fluid from leaking into other parts of the body where fluid is not meant to accumulate. Which is why, people with low albumin-levels in the blood often have swollen hands and legs from fluid accumulation.
- pH balance: Some of the electrolytes present in blood plasma play the role of ‘buffers’. That is, they ensure the pH is in the normal range which is required to support cell function.
- Transportation: Plasma acts as a carrier, transporting electrolytes, hormones and nutrients like sugars and fats in the blood to various cells and tissues of the body. All of these are required for carrying out various functions including cell growth, cell repair and normal functioning of cells.
- Waste management: When old cells in the body are broken down and new cells formed, the breakdown releases a lot of waste products. These are transported by blood plasma to the skin, lungs, kidneys and liver, where they are further broken down and sent out of the body as sweat, urine, feces, and carbon-di-oxide (during exhalation).
- Body temperature: Plasma balances out the heat loss and heat gain in the body, thereby helping to maintain body temperature.
- Respiration: Plasma plays a very minor role in transporting oxygen. Although most of the hemoglobin is present in red blood cells, a tiny amount is present dissolved in the plasma. This helps transport a tiny fraction of oxygen to the body’s cells, while most of the oxygen comes from RBCs.
Why is Plasma donation done?
Plasma is called the gift of life. People are encouraged to donate blood plasma as often as possible. This is because, after the RBC, WBC and platelets are removed, the dissolved components in plasma can be concentrated and used to treat several health conditions. This includes:
- Treating infectious diseases: If a person has just suffered from a bout of infectious disease and is now recovering, his/her plasma is rich in antibodies that successfully fought the infecting pathogen. So when the plasma of such a person is harvested, it can be given to another person suffering from the same disease. The antibodies that are now introduced from the donor’s plasma will help the recipient fight off the infection. Such plasma is called convalescent plasma. This strategy is used to fight chickenpox and more recently Covid-19. The convalescent plasma can also be sent to a laboratory where the antibodies are concentrated and vaccines made out of them.
- Treating Autoimmune disorders such as Hashimoto’s disease, Guillain-Barré syndrome, systemic lupus erythematosus, multiple sclerosis and myasthenia gravis.
- Treating blood disorders: Hemophilia is a rare condition in which the person’s blood plasma does not have enough clotting factors, so he/she is at the risk of bleeding out after an injury. Such people benefit from plasma donations which help augment clotting factors into their own plasma.
- Treating liver diseases such as acute liver failure and Wilson’s disease (copper starts accumulating in the liver)
- Treating neurological disorders: People suffering from inflammation of the brain and spinal cord, stroke, and viral or bacterial infections of the brain can benefit from the various benefits of blood plasma.
- Overcoming transplant rejection: People who have had a liver, heart or kidney transplant face the risk of the body rejecting the transplanted organ. Blood plasma is given to such people to help overcome this problem.
- Others: Both whole blood and blood plasma are used to treat victims of shock, burns, drug overdose, trauma (injury) and poisoning.
How is Plasma donated?
Whole-blood donation is simple and everyone is familiar with it. The procedure takes 30-40 minutes in which 1 pint of blood is collected from a person in one instance.
Blood plasma donation is a slightly-more involved process as the plasma has to be separated from the blood. This is done in 2 ways:
- Separated at source: The plasma is separated from the whole blood right at the time and place of donation using a special machine kept there. The process is called plasmapheresis. Such plasma is called source plasma. The RBCs and platelets are pumped back into the donor’s body.
- Recovered in a laboratory: The whole blood from the donor is collected in pouches and sent to a laboratory where the plasma is separated out using various techniques. Such plasma is called recovered plasma.
Any person wishing to donate plasma is first screened for weight, blood sugar, blood pressure and various health conditions including herpes, HIV and cancer. Once validated, he/she can donate as often as once in 14 days or 28 days, depending on the age. Plasma is largely made up of water, so it takes the body just 2 days to restore the normal volume of plasma while healthy food will restore its original level of contents. People of AB blood group are called universal plasma donors as their plasma is easily accepted by all blood groups.
Donation is required and encouraged as there are many patients across various ailments who require plasma. In fact, worldwide, the demand for plasma is always more than the supply.
What happens after plasma is donated?
Red-blood-cells have a short shelf life of just 6 weeks, which means, they cannot be stored for long. In contrast, plasma has the advantage that it can be frozen and stored for up to a year safely. Source plasma or recovered plasma is frozen and kept in cold storage. This is called FFP or fresh-frozen-plasma. FFP is then transported using refrigerated trucks to pharma companies who separate out the desired components to make the required medicines or vaccines.
Reviewed by Dr Suresh S Venkita, Group Medical Director, Kauvery Hospitals
Kauvery Hospital is globally known for its multidisciplinary services at all its Centers of Excellence, and for its comprehensive, Avant-Grade technology, especially in diagnostics and remedial care in heart diseases, transplantation, vascular and neurosciences medicine. Located in the heart of Trichy (Tennur, Royal Road and Alexandria Road (Cantonment), Chennai, Hosur, Salem, Tirunelveli and Bengaluru, the hospital also renders adult and pediatric trauma care.
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