In dehydration, what happens to hematocrit?

In dehydration, what happens to hematocrit?

• A. Increased hematocrit
• B. Decreased hematocrit
• C. No change
• D. Decreased plasma proteins

Answer: (A)

Hematocrit is the percentage of blood that is made up of red blood cells. In dehydration, fluid loss lowers the plasma volume while the red cell mass stays basically the same, causing the blood to become more concentrated. This hemoconcentration makes the red cells occupy a larger proportion of the blood, so the hematocrit increases. The effect is a relative change, not an increase in red cell production. Plasma proteins also rise with dehydration due to concentration, so decreased plasma proteins would not occur. When rehydration occurs, hematocrit typically moves back toward normal.

Hematocrit is the percentage of blood that is made up of red blood cells. In dehydration, fluid loss lowers the plasma volume while the red cell mass stays basically the same, causing the blood to become more concentrated. This hemoconcentration makes the red cells occupy a larger proportion of the blood, so the hematocrit increases. The effect is a relative change, not an increase in red cell production. Plasma proteins also rise with dehydration due to concentration, so decreased plasma proteins would not occur. When rehydration occurs, hematocrit typically moves back toward normal.