What is inside of blood?
After a blood draw, the blood is centrifuged in a centrifuge. After you have spun the tube, you will find three distinct layers: the top yellow layer is a layer of plasma which makes up about 55% of the mixture. About 90% of the plasma is water. Eight percent of the plasma are proteins: albumin, antibody, and fibrinogen. You can also find lipoproteins in this layer: chylomicrons, very low-density lipoproteins, low-density lipoproteins, and high-density lipoproteins. Two percent of the plasma are hormones, electrolytes, and nutrients. The middle white layer is about 1% of white blood cells and platelets. The deepest red layer is the red blood cells. They make up about 45% of the total mixture. Hemoglobin can be found in the red blood cells. Serum is very similar to plasma; except it does not contain fibrinogen and clotting factors like plasma. Hematocrit is volume taken up by red blood cells divided by total volume. In this case, hematocrit would be 45%. This person has a normal blood volume distribution.
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