This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Blood, Subject name: Pathology
[{'content': 'Normal PCV value is? \nSelect and explain. \nA. 30-35%, B. 40-45%, C. 50-55%, D. 60-65%', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e. 40-45% * Normal values are about 45% for men and about 42% for women.Hematocrit or Packed cell volume (PCV)* It is the proportion of blood volume that is occupied by red blood cells.* A decrease in the number or size of red cells also decreases the amount of space they occupy, resulting in lower hematocrit.* Similarly an increase in the number or size of red cells increases hematocrit.* Exceptions are thalassemia which can cause an increased number of red blood cells but a decreased size and hematocrit, and megaloblastic anemia which causes increase in size of red cells with decreased hematocrit", 'role': 'assistant'}]