Blood is made up of plasma, and the formed elements red blood cells, white blood cells, and platelets. A blood sample is collected and is determined to be 56% plasma and 1% white blood cells and platelets. What is the hematocrit of this blood sample?

43%

Explanation:

When you collect blood in a tube and centrifuge it, the elements that compose it separate in three distinct layers:

Plasma: water, proteins, nutrients. Buffy coat: white blood cells, platelets. Hematocrit: red blood cells.

If 56% of the blood sample is plasma and 1% is white blood cells and platelets, then the hematocrit is 100% - 56% - 1% = 43%.