A female has a blood test.One mL of her blood is drawn,spun in a centrifuge,and the plasma volume is measured and found to be 0.6 mL.Two months later the same patient returns to the doctor and,after doing another blood test,the doctor tells the patient that she has become anemic compared to her previous visit.Which of the following is most likely to be the woman's hematocrit on the second visit?

Question

Quizplus · Accepted Answer

Anemia is a condition in which there is a decrease in the number of red blood cells or a decrease in the amount of hemoglobin in the blood. Hematocrit is a measure of the percentage of red blood cells in the blood. If the patient became anemic, it means that there was a decrease in her hematocrit compared to her previous visit. Since the plasma volume remains relatively constant, the hematocrit can be estimated by subtracting the plasma volume from the total blood volume. Based on the given information, the total blood volume at the first visit was 1 mL (since 1 mL of blood was drawn), and the plasma volume was 0.6 mL. Therefore, the hematocrit at the first visit was 1 - 0.6 = 0.4 or 40%. On the second visit, if the patient became anemic, her hematocrit would be expected to be lower than 40%. The only answer choice that is lower than 40% is A) 35%, so it is the most likely hematocrit value on the second visit.

A Female Has a Blood Test