MCHpg
Typical optimal range
Optimal range varies by lab and individual context.
A typical adult reference range for MCH is roughly in the region of 27–33 pg, though exact thresholds vary between laboratories and analysers, so always interpret your result against your own lab's reference interval. These figures are indicative — the range printed on your own lab report is the definitive one for your results.
Interpretation of full blood count indices, including MCH, follows NHS laboratory medicine guidance and NICE guidelines on anaemia, including NG24 (coeliac disease), and the NICE guideline on vitamin B12 and folate deficiency (NG239 and associated quality standards).
What is MCH?
MCH, or Mean Corpuscular Haemoglobin, is a measure of the average amount of haemoglobin contained within a single red blood cell, expressed in picograms (pg). It is calculated automatically by a full blood count (FBC) analyser by dividing the total haemoglobin concentration by the red blood cell count. MCH is useful because it helps clinicians distinguish between different types of anaemia and understand whether red blood cells are carrying a normal, reduced, or elevated amount of the oxygen-carrying protein haemoglobin.
What a high MCH means
A raised MCH (macrocytic pattern) suggests that red blood cells contain more haemoglobin than usual, often because the cells themselves are larger than normal. This is not a diagnosis in itself, but it is a prompt for your GP to investigate the underlying cause.
- Vitamin B12 deficiency. Low B12 impairs DNA synthesis in developing red blood cells, causing them to grow larger than normal and carry more haemoglobin. This is one of the most common causes of a raised MCH in the UK, and your GP may check serum B12 alongside your FBC.
- Folate deficiency. Folate (vitamin B9) is essential for cell division in the bone marrow; a deficiency leads to the same pattern of large, haemoglobin-rich red cells as B12 deficiency, sometimes called megaloblastic anaemia. Dietary intake, malabsorption, and certain medications can all reduce folate levels.
- Alcohol excess. Regular heavy alcohol consumption is a well-recognised cause of macrocytosis and raised MCH in UK clinical practice, even in the absence of nutritional deficiencies. The effect can persist for several months after alcohol intake is reduced.
Hypothyroidism, liver disease, and certain medications (such as methotrexate or hydroxycarbamide) can also raise MCH. A single raised reading should always be interpreted in the context of the full blood count and your wider clinical picture.
What a low MCH means
A low MCH indicates that red blood cells contain less haemoglobin than usual (a hypochromic, often microcytic pattern), and this is the direction that most commonly warrants clinical follow-up, as it is frequently linked to iron deficiency or other conditions affecting haemoglobin production.
- Iron deficiency. Iron is required to synthesise haemoglobin; when body stores are depleted, red cells become smaller and paler and carry less haemoglobin. Iron deficiency is the most common cause of a low MCH worldwide and in the UK, and your GP is likely to check serum ferritin and iron studies alongside your FBC.
- Thalassaemia trait. Inherited thalassaemia traits (particularly beta-thalassaemia trait, which is more prevalent in South Asian, Mediterranean, and Middle Eastern populations) can cause persistently low MCH and MCV even when iron stores are normal. Your GP may request haemoglobin electrophoresis or HPLC to investigate.
A low MCH alongside other normal indices and no symptoms may sometimes reflect a haematological variant rather than a deficiency; your GP will look at the full blood count pattern before deciding whether further investigation is needed.
Should I be worried?
A single out-of-range MCH reading is rarely cause for alarm on its own, as the marker only becomes meaningful when interpreted alongside the rest of your full blood count (particularly MCV, haemoglobin, and red cell distribution width) and your symptoms and medical history. If your MCH is persistently outside the reference range on repeat testing, or if it is accompanied by symptoms such as fatigue, breathlessness, or pallor, it is worth booking a routine appointment with your GP. They may check iron studies, serum B12, folate, thyroid function, or liver function depending on which direction is abnormal and what else is found in your results. The good news is that many of the underlying causes are straightforward to identify and treat.
What actually helps
If a nutritional deficiency is identified as the cause of an abnormal MCH, the following lifestyle and dietary measures are supported by good evidence.
- Address iron intake and absorption. If iron deficiency is confirmed, your GP may recommend iron supplementation and dietary changes. Eating iron-rich foods alongside a source of vitamin C improves non-haem iron absorption, while avoiding tea or coffee with meals can also help.
- Ensure adequate B12 and folate. For those who are deficient, increasing intake through diet or supplementation (under GP guidance) is the primary treatment. Vegans and vegetarians are at particular risk of B12 deficiency and may need long-term supplementation or B12 injections depending on their levels.
- Reduce alcohol intake. If alcohol is contributing to a raised MCH, cutting down towards or below the UK Chief Medical Officers' low-risk guideline of 14 units per week can allow MCH to normalise over several months.
- Treat the underlying cause. Where MCH is abnormal due to a medical condition such as hypothyroidism, coeliac disease, or thalassaemia, managing that condition—under GP or specialist supervision—is the most important step.
There is good supporting evidence for the following foods in maintaining healthy haemoglobin production and red cell function.
Red meat and offal (e.g. liver)
Rich in haem iron, which is absorbed significantly more efficiently than non-haem iron from plant sources, and also provides vitamin B12.
Leafy green vegetables (e.g. spinach, kale)
Good sources of folate, which is essential for normal red blood cell development; also contain non-haem iron.
Eggs and dairy
Provide vitamin B12 and are an important source for vegetarians who include animal products in their diet.
Fortified breakfast cereals
Many UK breakfast cereals are fortified with iron, folate, and B12, making them a practical everyday source, particularly for those with lower meat intake.
Legumes (lentils, chickpeas, beans)
Good plant-based sources of folate and non-haem iron; best consumed with vitamin C-rich foods to enhance iron absorption.
Citrus fruits and peppers
High in vitamin C, which enhances the absorption of non-haem iron when eaten alongside iron-rich plant foods.
Track your own MCH
Upload a lab PDF and Better Days trends MCH over time, flags it when it drifts, and suggests foods that help.
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Sources & further reading
These are reputable UK health resources for further reading. This page is written to be consistent with their guidance but is not a substitute for them.
For information only — not medical advice, and not individually reviewed by a clinician. Reference ranges vary by lab and individual. Discuss any results with a qualified clinician before making changes.