Transfusion Medicine - Is Its Future Secure? - The Compositiion of Blood

Blood donors generally give whole blood.  In many cases, though, they donate plasma.  While some countries transfuse whole blood, more commonly, blood is separated into its primary components before it is tested and used in transfusion medicine.  Note the four primary components, their function, and the percentage of total blood volume each represents. 

PLASMA constitutes between 52 and 62 percent of whole blood.  It is a straw-colored fluid in which blood cells, proteins, and other substances  are suspended and transported. 

Water constitutes 91.5 percent of plasma.   Proteins, from which plasma fractions are derived constitute 7 percent of the plasma (including albumins, which make up about  4 percent of the plasma; globulins, about 3 percent; and fibrinogen, less than 1 percent). The remaining 1.5 percent of plasma is made up of other substances,  such as nutrients, hormones., respiratory gases, electrolytes, vitamins, and nitrogenous wastes. 

WHITE BLOOD CELLS  (Leukocytes) constitutes less than 1 percent of whole blood.  These attack and destroy potentially harmful foreign matter. 

PLATLETS  (thrombocytes) constitutes less than 1 percent of whole blood.  These form clots;  blocking blood from exiting wounds. 

Next time: Transfusion Medicine -Is Its Future Secure? -Conclusion of The Composition of Blood

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