Red Blood Corpuscles are the principal gas transporters of the body. They supply the essential oxygen to the tissues and carry carbon dioxide away to the lungs. RBCs are composed of Hemoglobin, the iron-containing blood pigment of the body which acts as the main vehicle behind the gas transportation. Mean Corpuscular Hemoglobin depicts the average amount of hemoglobin in RBCs. The number and physical features of Red blood Corpuscles change during illness. As an example, defective RBCs are produced or they can be attacked by body's own immune system (autoantibodies). Hence red blood cells provide the ample number of information about the health. Doctors may prescribe this test for a routine check-up along with a complete blood count or if someone is suffering from fatigue, splenomegaly, or difficulty to adapt altitude changes.