MCH (mean corpuscular haemoglobin) measures the average amount of haemoglobin contained in one of your red blood cells.
What might a low result mean?
MCH is looked at in the context of your other red cell blood markers. If your other markers are normal then a slightly low MCH level may not be significant.
Low MCH levels may be caused by anaemia, when the number of blood cells are low. Anaemia can be caused by iron deficiency, which can be caused by not consuming enough iron in the diet, or from conditions such as Crohn's disease where the intestines are unable to absorb sufficient iron. Other causes include gastrointestinal bleeds such as with peptic ulcers, and by a lack of vitamins such as B12 and folate.
What might a high result mean?
MCH is looked at in the context of your other red cell blood markers. If your other markers are normal then a slightly high MCH level may not be significant.
Elevated MCH levels may be a sign of macrocytic anaemia, where the red blood cells are too large and do not contain enough haemoglobin. This is most often caused by a lack of vitamin B12 and folate (either through diet or absorption problems) which can cause MCH levels to be either high or low, indicating the need of additional tests.
Elevated MCH levels can also be found in people with hyperthyroidism, liver disease and alcoholism.