MCHC (mean corpuscular haemoglobin concentration) measures the average concentration of haemoglobin within red blood cells — how densely packed the haemoglobin is per unit volume of cell. It is the most physiologically direct measure of red cell haemoglobin content.

Low MCHC indicates hypochromic anaemia where red cells are dilute in haemoglobin — most commonly from iron deficiency. Elevated MCHC is seen in hereditary spherocytosis (where red blood cells are abnormally spherical and dense) and can also be a laboratory artifact from haemolysis or hyperglycaemia. MCHC provides a useful check on other red cell indices and helps identify hereditary red cell disorders.