Physiology Concentration of methemoglobin to appears cyanosis: (PGI June 2007) A 5 gm/di B 2gm/df C 1.5gm/dl D 12 gm/di 💡 Explanation Concentration of methemoglobin to appears cyanosis: (PGI June 2007) ✓ Correct Answer: C. 1.5gm/dl