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Blood Basics > Blood in the Body

Blood Plasma

Human blood is a highly complex substance. Its major components are red blood cells, which carry oxygen from the lungs to the body tissues; white blood cells, which have major roles in disease prevention and immunity; and platelets, which are key elements in the blood clotting process. These blood elements are suspended in blood plasma, a yellowish liquid that comprises about 55% of human blood.

Plasma is the transporting medium for a myriad of hormones, electrolytes, sugars, waste products, and other substances. It is especially useful in transfusion medicine, as it provides the starting material for the preparation of critical blood-clotting factors, albumin and immune protein preparations. The clotting factor concentrates, prepared from large batches of pooled plasma, provide life-saving treatment for blood clotting disorders such as hemophilia.

-- Richard J. Davey, M.D.
Chief Medical Officer
New York Blood Center