Mean corpuscular haemoglobin concentration (MCHC) is the average concentration of haemoglobin in red blood cells. It is a value you will see reported as part of a Full Blood Count (FBC) test. MCHC is one of the red blood cell (RBC) indices, and it is used to help diagnose the type, cause, and severity of anaemia.
MCHC is used to follow conditions when you are under treatment for a disease, to look for signs of anaemia and infection. It is also one the tests that is done to monitor your overall health.
The total amount of haemoglobin in a red cell is measured in the mean cell haemoglobin (MCH) part of the FBC, but that usually just mirrors the size of the red cells. The MCHC tells you whether those cells pack in more or less haemoglobin than usual. This results in the red cells appearing more or less red, as haemoglobin is what gives them their red colour.
A high MCHC is known as hyperchromia, with a higher concentration of haemoglobin in each red cell than is normal. High MCHC levels are seen in autoimmune haemolytic anaemia and in burn patients. They may also occur in hereditary spherocytosis, which is a rare disorder.
A low MCHC means that there is less haemoglobin in each red cell regardless of the size of the red cell, known as hypochromia. It is seen in iron deficiency anaemia and thalassemia. This type of anaemia can be caused by insufficient iron in the diet, or the inability to absorb it or use it to make haemoglobin.