This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Blood disorder, Subject name: Pathology
Elevated ESR is seen in following conditions except: 
Select and explain. 
A. Polymyositis rheumatica, B. Multiple myeloma, C. Temporal aeritis, D. Polycythemia rubra
D: Polycythemia rubra
Answer: D: Polycythemia rubra 
Explanation: Polycythemia rubra: Elevated hemoglobin level and hematocrit: due to increased number of red blood cells * Platelet count or white blood cell count may also be increased. Erythrocyte sedimentation rate (ESR) is decreased due to an increase in zeta potential. Low erythropoietin (EPO) levels.