In a typical 70 kg adult, how many liters of plasma are present (intravascular space)?

In a typical 70 kg adult, how many liters of plasma are present (intravascular space)?

• A. 3 L
• B. 16 L
• C. 23 L
• D. 42 L

Answer: (A)

Intravascular plasma volume is the fluid part of blood inside the vessels. For a typical 70 kg adult, total blood volume is about 5 L. Plasma makes up roughly 55% of that blood, which gives around 2.7 L. With a hematocrit of about 45%, the red cell volume is ~2.2 L, leaving plasma about 2.7 L. Rounding, this is commonly stated as about 3 L of plasma in the intravascular space. For context, the extracellular fluid is about 14 L in total, with plasma around 3 L and interstitial fluid about 11 L.

Intravascular plasma volume is the fluid part of blood inside the vessels. For a typical 70 kg adult, total blood volume is about 5 L. Plasma makes up roughly 55% of that blood, which gives around 2.7 L. With a hematocrit of about 45%, the red cell volume is ~2.2 L, leaving plasma about 2.7 L. Rounding, this is commonly stated as about 3 L of plasma in the intravascular space. For context, the extracellular fluid is about 14 L in total, with plasma around 3 L and interstitial fluid about 11 L.