This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Polycythemia, Subject name: Medicine
Which is not seen in polycythemia vera : 
Select and explain. 
A. Increased vitamin B12 binding capacity, B. Increase erythropoietin level, C. Increase RBC count, D. Ocular congestion
B: Increase erythropoietin level
Answer: B: Increase erythropoietin level 
Explanation: Ans. is 'b' increased erythropoietin level. In polycythemia Vera increase in erythrocytes occur without any increase in level of erythropoietin. In fact erythropoietin level is decreased due to feedback by increased erythrocytes.