Plasma is the liquid component of blood that remains after all blood cells (red blood cells, white blood cells, and platelets) have been removed through a process called centrifugation. Plasma contains water, electrolytes, proteins (including clotting factors like fibrinogen), hormones, waste products, and various nutrients. Plasma contains all the clotting factors which are essential for coagulation to occur. These clotting factors are present in their inactive forms and become activated during the clotting process to help control bleeding.
Serum is the liquid portion of blood that remains after the blood has clotted and the clot is removed by centrifugation. Since clotting factors like fibrinogen are utilized during the clotting process, they are absent in serum. However, serum contains other proteins, electrolytes, hormones, and waste products. Plasma can also be clotted using calcium or serum activator tubes to produce serum.
When an individual donates blood, it undergoes separation into distinct components to cater to specific patient requirements. Blood is divided into red blood cells, white blood cells, platelets, and plasma proteins. Among the blood proteins are notable examples like serum albumin, globulins, fibrinogen, and plasminogen. For example, if a patient is afflicted with liver failure or coagulation disorders, administration of blood plasma, rich in clotting factors, may be warranted. Human serum represents the residual fluid after the removal of fibrinogen and encompasses proteins including albumin and immunoglobulins.
Human serum albumin is a circulating transporter of exogenous and endogenous molecules within the bloodstream. Substances stick to albumin molecules within the serum and are carried by it. Human serum thus helps in the transportation of fatty acids and thyroid hormones which act on most of the cells found in the body.
Thyroid hormones are essential to the proper development and functioning of the body because they help to regulate bone growth and maturation, carry out protein synthesis and increase the body’s basal metabolic rate. Human serum also helps transport other hormones which are fat soluble.
Due to its unique role as a circulating carrier, human serum is used in the protein binding of many drugs to facilitate drug distribution within the body. Human serum is used to distribute antibiotics in the body and albumin allows the curable substances in the antibiotics to be bound and carried out throughout the body.
Human off-the-clot serum is serum that has been allowed to coagulate naturally after collection and has not been exposed to any anticoagulants. This human off-the-clot serum is ideal for metabolic studies because it is available in the original transfer packs straight from individual donors.
Human AB serum is collected from type AB donors and it lacks antibodies against blood type A and B antigens. AB donors are universal donors because their blood can be given to individuals with any blood type during plasma transfusions. Human AB serum is used in cell culture applications, cell therapy, transplantation, and tissue engineering.
Human complement serum is collected, clotted, and frozen with 4 hours after donation. This special processing is designed to preserve the complement system and prevent activation of the complement cascade. Complement plays a critical role in immune defense and inflammation, and is activated when antibodies in an immune animal interact with corresponding antigens. Human complement serum is used to study immune reactions, host-pathogen interactions, autoimmune disorders, and inflammatory responses.