Mean Corpuscular Haemoglobin (MCH)

Mean Corpuscular Haemoglobin (MCH) is the average amount of haemoglobin contained in each red blood cell. Haemoglobin is the protein that carries oxygen around your body. MCH is calculated from a standard full blood count and sits alongside other red cell indices like MCV (cell size) and MCHC (haemoglobin concentration) to help describe how well your red blood cells are built and how effectively they carry oxygen.

MCH helps flag patterns that point toward common, fixable nutrient issues and lifestyle factors long before bigger problems arise. Most issues with MCH are also linked to changes in haemoglobin and red cell count, so it is important to track these markers together. 

• Low MCH often coincides with small, pale cells and usually points toward iron deficiency or inherited haemoglobin conditions such as thalassaemia. Low iron means less haemoglobin per cell and less oxygen delivery, which can show up as fatigue, brain fog, reduced exercise capacity, and feeling cold.
  

• High MCH typically occurs with larger red cells and is most often linked to low vitamin B12 or folate, alcohol overuse, thyroid problems, or liver disease. Persistently high MCH can be a clue that your nervous system and metabolic health need attention, because B12 and folate are critical for nerve function and DNA repair.
  

Tracking MCH over time with the other indices gives a clearer view of how your nutrition, alcohol intake, gastrointestinal absorption, and overall metabolism are affecting oxygen delivery. This is valuable for prevention, not just diagnosis.

MCH is influenced by nutrient intake, red blood cell production, and oxygen demands. Factors that commonly affect it include:

• Iron deficiency: Insufficient dietary iron or poor absorption lowers haemoglobin content and MCH.

• Vitamin B12 or folate deficiency: Impairs red blood cell formation, leading to larger cells with higher MCH.

• Chronic inflammation: Restricts iron use and lowers MCH even when stores appear adequate.

• Blood loss: Reduces iron and haemoglobin, lowering MCH.

• Liver or thyroid dysfunction: Can raise MCH due to changes in red cell size and metabolism.

• Alcohol intake: Excessive consumption may increase MCH by affecting bone marrow and cell development.

• Medication use: Chemotherapy drugs, antiretrovirals, or anticonvulsants can alter red blood cell production and MCH.

Reference ranges:

• Optimal: 27–33 pg/cell

• Very low: <25.0 pg/cell

• Mildly low: 25.0–26.9 pg/cell

• Elevated: >33 pg/cell

If your MCH is low:

Focus on improving iron intake and absorption. Include heme-iron foods such as red meat, liver, chicken thighs, and sardines, and non-heme sources like lentils, spinach, and tofu paired with vitamin C–rich foods to boost absorption. Avoid drinking tea or coffee with meals, as they can reduce iron uptake.

Ensure adequate B-vitamin intake (especially B12, folate, and B6) through foods such as eggs, leafy greens, legumes, salmon, and beef. If levels remain low, consider a targeted iron or B-vitamin supplement under practitioner guidance.

If your MCH is high:

Review B12 and folate levels — these are common causes of elevated MCH. Limit alcohol intake and support liver function with antioxidant-rich foods such as cruciferous vegetables, berries, and turmeric. If high levels persist, discuss with your healthcare provider, as elevated MCH can sometimes reflect underlying liver, thyroid, or marrow disorders.

1. Mean Corpuscular Hemoglobin (MCH). Cleveland Clinic, 2024. Available from: https://my.clevelandclinic.org/health/diagnostics/mch-blood-test

2. Red Blood Cell (RBC) Indices. MedlinePlus, U.S. National Library of Medicine, 2024. Available from: https://medlineplus.gov/lab-tests/red-blood-cell-rbc-indices/

3. Iron – Health Professional Fact Sheet. Office of Dietary Supplements, National Institutes of Health, 2024. Available from: https://ods.od.nih.gov/factsheets/Iron-HealthProfessional/

4. Stoffel NU, Zeder C, Brittenham GM, Moretti D, Zimmermann MB. Iron absorption from supplements is greater with alternate day than with consecutive day dosing in iron-deficient women. Haematologica, 2020. Available from: https://haematologica.org/article/view/9379

5. Macrocytosis: What causes it? Mayo Clinic, 2025. Available from: https://www.mayoclinic.org/diseases-conditions/vitamin-deficiency-anemia/expert-answers/macrocytosis/faq-20058234