Blood plasma is the straw-colored liquid component of blood, constituting about 55% of its total volume. This fluid acts as the body’s transportation system, carrying water, salts, enzymes, hormones, and proteins like albumin, globulins, and clotting factors to all tissues and organs. Plasma supports blood volume and pressure, regulates pH balance, and aids in blood clotting and immune defense. Plasma is collected through a specialized donation process called plasmapheresis, which separates and harvests the plasma while safely returning other blood parts to the donor.
Donor Eligibility and Preparation
To ensure the safety of both the donor and recipient, strict qualification requirements must be met. Donors must be at least 18 years old, weigh a minimum of 110 pounds (50 kilograms), and be in good health. A comprehensive medical history screening is conducted on the first visit and repeated regularly, often annually, to confirm continued eligibility.
Each donation requires a mini-physical, where staff check vital signs, including blood pressure, pulse, temperature, and weight. A small blood sample is also taken, usually via a finger prick, to test protein and hematocrit (red blood cell volume) levels. This ensures the donor’s protein levels are sufficient for safe plasma removal and confirms they are not anemic.
Proper preparation is necessary to ensure a smooth donation experience. Donors are advised to hydrate thoroughly in the 24 hours before the appointment, as plasma is over 90% water. Hydration helps maintain blood volume and makes the venipuncture more successful. Eating a nutritious, non-fatty meal a few hours prior is also recommended, since excessive fats can negatively affect the quality of the collected plasma.
The Plasma Collection Procedure
The plasma collection process is an automated technique known as plasmapheresis, which separates whole blood into its components outside the body. The procedure begins when a trained technician performs a venipuncture, usually in the arm, inserting a sterile, single-use needle into a vein. Whole blood is then drawn from the donor and directed into the apheresis machine.
Inside the machine, the blood is mixed with an anticoagulant, most commonly citrate, to prevent clotting. The anticoagulated blood then enters a centrifuge, which rapidly spins the fluid to separate components based on density. Heavier components—red blood cells, white blood cells, and platelets—are forced outward, while the lighter, liquid plasma remains in the center.
Once separated, the plasma is channeled into a sterile collection container. The remaining cellular components are returned to the donor through the same needle, often mixed with a small amount of saline solution to maintain circulating blood volume and hydration. The process of drawing, separating, and returning the blood occurs in cycles, collecting approximately 500 to 800 milliliters of plasma over the session.
The entire procedure is closely monitored by staff and typically takes about 45 to 60 minutes for returning donors, though the initial visit may be longer. The apheresis machine ensures blood cells are returned efficiently, minimizing their loss and allowing healthy individuals to donate plasma more frequently than whole blood.
Post-Collection Care and Potential Side Effects
Immediate care focuses on recovery before the donor leaves the facility. Donors are asked to remain in a monitored recovery area for 10 to 15 minutes to rest and rehydrate. It is important to continue drinking water or electrolyte-rich fluids for several hours afterward to replenish the liquid volume removed.
The bandage should remain in place for at least two hours to prevent bleeding and allow the site to close. Donors should avoid strenuous activity or heavy lifting with the donation arm for the remainder of the day. Keeping the area clean and dry helps reduce the risk of infection.
Most side effects are minor and temporary, stemming from the temporary reduction in blood volume. Lightheadedness, dizziness, or fatigue are the most common symptoms and are resolved by resting and rehydrating. Some donors may experience a tingling sensation around the mouth or in the fingers, a sign of a mild citrate reaction caused by the anticoagulant binding to calcium.
If symptoms like persistent dizziness, severe nausea, or unusual pain occur, the donor should seek medical attention. Plasma donation is generally safe, and staff are trained to recognize and manage adverse reactions promptly. Regular donors are encouraged to maintain a healthy diet rich in protein, as plasma proteins are removed during collection.
Therapeutic Applications of Plasma
Collected plasma is a medically valuable resource that cannot be artificially manufactured, making human donation the only source for life-saving treatments. The plasma is frozen and sent to specialized facilities to be processed into plasma-derived medicinal products (PDMPs) through fractionation. This process separates specific proteins, such as albumin, immunoglobulins, and clotting factors, for therapeutic use.
Immunoglobulins (antibodies) are used to treat primary and secondary immune deficiencies where a patient cannot produce enough functioning antibodies. These treatments fortify the immune system and prevent severe, recurrent infections. Clotting factors are concentrated and given to patients with bleeding disorders like hemophilia, replacing the proteins necessary for blood coagulation.
Albumin, the most abundant protein in plasma, is used to manage shock, severe burns, and trauma by helping to restore lost blood volume and maintain blood pressure. Other specialized PDMPs treat rare conditions, including Alpha-1 Antitrypsin Deficiency, a genetic disorder affecting the lungs, and Hereditary Angioedema. The demand for these products is consistently high, underscoring the importance of the plasma collection process for patients with chronic and complex diseases.