High hemoglobin with low erythropoietin levels is most characteristic of which condition?

• A. Iron overload
• B. Secondary polycythemia
• C. Polycythemia vera
• D. Anemia of chronic disease

Answer: (C)

High hemoglobin with inappropriately low erythropoietin means the red cell production is driven independently of erythropoietin signaling. In normal physiology, EPO rises when oxygen delivery is low to stimulate RBC production; when RBC mass becomes high but EPO remains low, it points to a primary, autonomous production mechanism. This pattern fits polycythemia vera, a JAK2-mutant myeloproliferative disorder where red cell production runs on its own. The body senses the increased red cells and suppresses EPO through negative feedback, distinguishing it from secondary polycythemia, where low oxygen or tumor EPO production drives high EPO levels, or from conditions like anemia-related states where Hb is not elevated.