Mean Corpuscular Hemoglobin (MCH)
MCH is the average amount of haemoglobin inside a single red blood cell. Tracks tightly with MCV — both fall in iron-deficiency anaemia, both rise in B12 / folate deficiency.
What it measures
MCH is computed as total haemoglobin divided by red-cell count. It tells you, on average, how much haemoglobin each red cell carries. In nearly all clinical situations MCH and MCV move together — anaemias with small cells (microcytic) also have less haemoglobin per cell (hypochromic), and anaemias with large cells (macrocytic) have more haemoglobin per cell. The diagnostic value of MCH alongside the rest of the CBC is sorting anaemia into the standard categories: microcytic-hypochromic (low MCV, low MCH — iron deficiency, thalassaemia, anaemia of chronic disease), normocytic (acute blood loss, early renal disease), macrocytic (B12, folate, alcohol, hypothyroidism, drug-induced).
What a high value can mean
- B12 or folate deficiency — macrocytic anaemia; MCV and MCH both rise.
- Hypothyroidism — modest macrocytosis.
- Chronic alcohol use — direct marrow toxicity.
- Drug-induced (methotrexate, hydroxyurea, zidovudine) — interfere with DNA synthesis.
- Liver disease — circulating lipid changes alter the cell membrane.
What a low value can mean
- Iron-deficiency anaemia — by far the commonest cause; MCV and MCH both fall, ferritin low.
- Thalassaemia trait — MCV often very low with mildly low MCH; haemoglobin electrophoresis distinguishes from iron deficiency.
- Anaemia of chronic disease — usually normocytic but can drop into microcytic territory.
- Sideroblastic anaemia — rare; defective haem synthesis.
When to discuss with a doctor
MCH is part of the diagnostic conversation in any anaemia work-up, not a stand-alone test. The pattern alongside haemoglobin, MCV, RDW and ferritin sorts the cause into the standard buckets. Mediora.AI surfaces the CBC pattern as a whole; the underlying-cause work-up belongs with a primary-care doctor.