MCH: Abbreviation for mean cell hemoglobin, which is the average amount of hemoglobin in the average red cell. The MCH is a calculated value derived from the measurement of hemoglobin and the red cell count. (The hemoglobin value is the amount of hemoglobin in a volume of blood while the red cell count is the number of red blood cells in a volume of blood.) It is a standard part of the complete blood count.