Blood fractionation is a process that separates whole blood into its individual components. This allows for specialized medical treatments, as different parts of the blood serve distinct functions. By isolating these components, healthcare professionals can administer specific therapies tailored to a patient’s needs, rather than using whole blood. This approach has become a fundamental aspect of modern medicine, enabling the treatment of a wide array of conditions and improving patient outcomes.
The Components of Blood
Whole blood consists of several distinct components, each with specialized roles. Approximately 55% of blood volume is plasma, a yellowish liquid that serves as the matrix for other blood elements. Plasma is primarily water, but it also contains dissolved proteins, salts, nutrients, hormones, and waste products.
Suspended within the plasma are the cellular components, which make up about 45% of the blood’s volume. Red blood cells, or erythrocytes, are the most numerous, responsible for transporting oxygen from the lungs to the body’s tissues and carrying carbon dioxide back to the lungs for exhalation. These cells contain hemoglobin, a protein that binds oxygen and gives blood its characteristic red color.
White blood cells, or leukocytes, are a diverse group of cells that form an important part of the body’s immune system, defending against infections and foreign invaders. Platelets, also known as thrombocytes, are small cell fragments that play an important role in blood clotting, forming plugs to stop bleeding when a blood vessel is injured.
What is Blood Fractionation?
Blood fractionation begins with the separation of whole blood into its major components, typically through centrifugation. In this method, collected blood is spun at high speeds, causing denser cellular elements to settle at the bottom of a tube. This leaves lighter, liquid plasma at the top, and a thin layer known as the “buffy coat” in the middle, which contains white blood cells and platelets.
Once plasma is separated, it undergoes further processing to isolate its various protein components. This step is known as plasma protein fractionation. One widely used technique is cold ethanol precipitation, also known as the Cohn method. This process involves carefully adjusting the temperature and alcohol concentration of the plasma in a series of steps.
By altering these conditions, specific proteins like albumin, immunoglobulins, and clotting factors become insoluble and precipitate out of the solution. These precipitated proteins are then collected, purified, and prepared for medical use. Other methods, such as chromatography, may also be employed to further refine and separate plasma proteins based on differences in their size or chemical properties, yielding highly purified and concentrated therapeutic products.
Applications of Blood Fractions in Medicine
The separated blood fractions have widespread applications in medical treatment, addressing a range of conditions. Albumin, a protein derived from plasma, is often used to restore blood volume in patients who have experienced significant fluid loss due to burns, trauma, or surgery. It also helps maintain oncotic pressure, preventing fluid leakage from blood vessels into tissues, and can be administered in cases of severe liver disease where the body cannot produce enough albumin.
Immunoglobulins, also known as antibodies, are used to treat immune deficiencies, such as common variable immunodeficiency, by providing patients with protective antibodies they lack. They are also employed in the management of certain autoimmune conditions, where the body’s immune system mistakenly attacks its own tissues, by modulating the immune response. This helps patients fight off infections and manage chronic inflammatory diseases.
Clotting factors, such as Factor VIII and Factor IX, are extracted from plasma and are important for individuals with bleeding disorders like hemophilia A and B. These patients lack specific proteins needed for proper blood clotting, and infusions of the concentrated factors allow their blood to clot effectively, preventing or controlling severe bleeding episodes. Other plasma-derived products, including antithrombin, are used to manage certain thrombotic conditions, helping to regulate blood coagulation.
Ensuring Safety and Availability
Ensuring the safety of blood fractions is important, beginning with rigorous donor screening. Donors undergo thorough evaluations for overall health and are screened for infectious diseases, including hepatitis B and C viruses, HIV, and other potential pathogens. This initial step helps minimize the risk of transmitting infections through donated blood.
During manufacturing, methods are employed for viral inactivation and pathogen removal. These techniques, which may include heat treatment, solvent/detergent treatment, or nanofiltration, are designed to neutralize or eliminate viruses and other infectious agents that might be present in the plasma pool. These multi-step purification processes enhance the safety profile of the final products.
Regulatory bodies, such as national health agencies, play an important role in overseeing the production and quality of blood fractions. They establish strict guidelines for manufacturing practices, conduct inspections, and review product testing data to ensure all products meet high standards for purity, potency, and safety before release for clinical use. The global supply chain for blood fractions also faces ongoing challenges, including the continuous need for voluntary blood donations to meet patient demand.