In a typical healthy adult, approximately what percentage of whole blood volume is plasma?

• A. About 75%
• B. About 55%
• C. About 25%
• D. About 45%

Answer: (B)

Verified step by step guidance

1. Understand that whole blood is composed of two main components: plasma and formed elements (such as red blood cells, white blood cells, and platelets).
2. Recall that plasma is the liquid portion of blood, which carries nutrients, hormones, and waste products, and typically makes up the majority of blood volume.
3. Remember the typical percentage ranges: plasma usually accounts for about 55% of the total blood volume, while the formed elements make up the remaining 45%.
4. Recognize that the question asks for the approximate percentage of plasma in whole blood volume, so focus on the plasma proportion rather than the formed elements.
5. Conclude that the correct approximate percentage of plasma in whole blood volume in a healthy adult is about 55%.