Science, Tech, Math › Science What Is the Chemical Composition of Blood? Find out What This Vital Life Fluid Is Made Of Share Flipboard Email Print Dana Neely / Getty Images Science Chemistry Biochemistry Basics Chemical Laws Molecules Periodic Table Projects & Experiments Scientific Method Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated November 03, 2019 Blood is slightly denser and is approximately three to four times more viscous than water. Blood consists of cells that are suspended in a liquid. As with other suspensions, the components of blood can be separated by filtration. However, the most common method of separating blood is to centrifuge (spin) it. Three layers are visible in centrifuged blood. The straw-colored liquid portion, called plasma, forms at the top (~55%). The buffy coat, a thin cream-colored layer consisting of white blood cells and platelets forms below the plasma, while red blood cells comprise the heavy bottom portion of the separated mixture (~45%). What Is the Volume of Blood? Blood volume is variable but tends to be about 8% of body weight. Factors such as body size, the amount of adipose tissue, and electrolyte concentrations all affect blood volume. The average adult has about 5 liters of blood. What Is the Composition of Blood? Blood consists of cellular material (99% red blood cells, with white blood cells and platelets making up the remainder), water, amino acids, proteins, carbohydrates, lipids, hormones, vitamins, electrolytes, dissolved gasses, and cellular wastes. Each red blood cell is about one-third hemoglobin, by volume. Plasma is about 92% water, with plasma proteins as the most abundant solutes. The main plasma protein groups are albumins, globulins, and fibrinogens. The primary blood gasses are oxygen, carbon dioxide, and nitrogen. Sources "Hole's Human Anatomy & Physiology, 9th Edition," McGraw Hill, 2002.