High MCV and MCH: What These Blood Test Results Can Mean

By Your Health Magazine Health Information Team

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High MCV and MCH: What These Blood Test Results Can Mean

Updated August 18, 2026 by the editorial team at Your Health Magazine.

High MCV and MCH usually mean that your red blood cells are larger than the laboratory’s reference range and contain more hemoglobin per cell. A high MCV is called macrocytosis. Common causes include vitamin B12 or folate deficiency, regular heavy alcohol use, liver disease, hypothyroidism, certain medications, and an increase in young red blood cells after bleeding or red-cell destruction.

These results do not automatically mean that you have anemia or a serious disease. MCH often rises because a larger red blood cell can hold more total hemoglobin; it does not necessarily mean that hemoglobin is too concentrated. Your clinician must interpret MCV and MCH with the rest of the complete blood count, your symptoms, medication and alcohol history, and changes over time.

Quick Guide to MCV, MCH, and Related CBC Results

For a broader explanation of the test, see What Does a CBC Without Differential Reveal About Your Health?

Understanding Elevated MCV and MCH Levels

MCV stands for mean corpuscular volume and measures average red blood cell size. MCH stands for mean corpuscular hemoglobin and measures the average amount of hemoglobin in each red blood cell. Hemoglobin is the protein that carries oxygen.

When MCV is high, the cells are described as macrocytic. Because larger cells often contain more hemoglobin in total, MCH may rise at the same time. This relationship is why MCV usually provides more useful diagnostic direction than an isolated MCH result. Neither value can identify a cause on its own.

Macrocytosis can occur with or without anemia. Anemia is determined mainly by the hemoglobin, hematocrit, and red blood cell count—not by MCV or MCH alone. A person may therefore have high MCV and MCH but normal hemoglobin and no symptoms.

Common Causes of High MCV and MCH

Vitamin B12 or Folate Deficiency

Vitamin B12 and folate are needed for normal DNA production as red blood cells develop. A deficiency can disrupt cell division and produce unusually large cells, sometimes causing megaloblastic anemia. Deficiency may result from limited dietary intake, pernicious anemia, gastrointestinal disease or surgery, medication effects, or other absorption problems. Pregnancy increases folate needs.

Vitamin B12 deficiency can also affect nerves, even when anemia is mild or absent. Possible symptoms include numbness or tingling, balance problems, memory or concentration changes, and a sore or smooth tongue.

Alcohol Use and Liver Disease

Regular heavy alcohol use is a common cause of macrocytosis and may raise MCV even when a person is not anemic. Alcohol can affect red blood cell development directly and may also contribute to poor nutrition or folate deficiency. Liver disease can alter red blood cell membranes and produce a similar pattern.

Hypothyroidism

An underactive thyroid can be associated with macrocytosis or anemia. When symptoms or medical history suggest a thyroid problem, a clinician may include thyroid-stimulating hormone testing in the evaluation.

Medications

Some chemotherapy medicines, antiretroviral therapy, seizure medicines, and medications that interfere with DNA or folate metabolism can increase MCV. Do not stop a prescription because of a blood-test result. Ask the prescribing clinician whether the change is expected and whether follow-up testing is needed.

Reticulocytosis After Bleeding or Red-Cell Destruction

Reticulocytes are newly released red blood cells and are larger than mature cells. If the bone marrow is rapidly replacing cells after blood loss or hemolysis, the temporary increase in reticulocytes can raise MCV. A reticulocyte count helps identify this pattern.

Less Common Bone Marrow Disorders

Persistent unexplained macrocytosis—especially when accompanied by low white blood cells, low platelets, worsening anemia, or abnormal cells on a blood smear—can occasionally be related to a bone marrow disorder such as myelodysplastic syndrome. High MCV by itself does not mean cancer, but an unexplained or changing pattern should be evaluated.

Do High MCV and MCH Cause Symptoms?

High MCV and MCH usually do not cause symptoms by themselves. Symptoms come from anemia or the underlying condition. Some people have no symptoms, particularly when the abnormality is mild and hemoglobin remains normal.

Possible anemia-related symptoms include:

Fatigue, weakness, or reduced exercise tolerance

Shortness of breath

Dizziness or headaches

Pale skin

A fast or irregular heartbeat

Symptoms such as numbness, tingling, balance difficulty, confusion, or memory changes deserve prompt attention because they may occur with vitamin B12 deficiency and can develop even without severe anemia.

How Clinicians Evaluate High MCV and MCH

A single mildly abnormal result may be repeated, especially if previous results were normal and there are no symptoms. Evaluation is guided by how high the values are, whether they remain elevated, whether anemia or other low blood-cell counts are present, and the person’s medical history.

Depending on the situation, the evaluation may include:

Reviewing the full CBC: hemoglobin, hematocrit, red blood cell count, RDW, MCHC, white blood cells, and platelets.

Comparing previous results: a persistent or rising pattern is more informative than one isolated test.

A peripheral blood smear: allows a trained professional to examine red blood cell size and shape.

A reticulocyte count: shows whether the bone marrow is releasing more young red blood cells.

Nutrient testing: vitamin B12 and folate, with methylmalonic acid or homocysteine in selected cases.

Other laboratory tests: liver tests and thyroid testing when clinically appropriate.

History review: diet, alcohol intake, gastrointestinal conditions or surgery, pregnancy, medications, and symptoms.

A primary care clinician can begin this evaluation. Referral to a hematologist may be appropriate when the cause remains unclear, the abnormality is significant or worsening, more than one type of blood cell is low, or the blood smear is concerning.

Treatment Depends on the Cause

There is no single treatment for high MCV and MCH. The goal is to identify and address the reason for the abnormal results. Treatment may involve correcting a confirmed vitamin deficiency, managing thyroid or liver disease, addressing alcohol use, or adjusting a medication under medical supervision. Bone marrow disorders require specialist evaluation and condition-specific treatment.

Do not assume that iron is needed. High MCV is not the typical pattern of iron deficiency, and unnecessary iron can be harmful. It is also wise to speak with a clinician before taking folic acid for unexplained macrocytosis. Large amounts of folate can improve the anemia caused by vitamin B12 deficiency without correcting the related nerve damage, potentially delaying recognition of the B12 problem.

When to Call a Clinician

Contact the clinician who ordered the blood test if MCV or MCH is newly high, remains elevated on repeat testing, is accompanied by low hemoglobin or other abnormal blood counts, or occurs with unexplained fatigue, weakness, shortness of breath, weight loss, jaundice, easy bruising, numbness, tingling, balance problems, or cognitive changes.

Seek urgent medical care for chest pain, severe trouble breathing, fainting, new confusion, or rapidly worsening symptoms. These symptoms should not be attributed to MCV or MCH without an evaluation.

Can High MCV and MCH Be Prevented?

Not every cause is preventable. A balanced diet can help prevent some nutrient deficiencies, but absorption disorders, medications, thyroid disease, liver disease, and bone marrow conditions require medical assessment. If alcohol may be contributing, discuss safe next steps with a healthcare professional; people who may be physically dependent should not stop abruptly without medical guidance.

Regular checkups are useful when a person has a condition or medication that requires CBC monitoring. Testing frequency should be based on the cause and treatment plan rather than a fixed schedule for everyone.

Frequently Asked Questions

What are normal MCV and MCH ranges?

Many laboratories use an MCV range near 80–100 femtoliters and an MCH range near 27–33 picograms per cell. Reference ranges vary by laboratory, testing method, age, and other factors, so use the range printed on your own report.

Is high MCH the same as high MCHC?

No. MCH is the amount of hemoglobin in an average red blood cell. MCHC is the concentration of hemoglobin relative to the cell’s volume. MCH can rise simply because the cells are larger while MCHC remains normal.

Can high MCV occur without anemia?

Yes. Macrocytosis may be found before anemia develops or may occur without anemia, including in some people who use alcohol regularly or take certain medications. The hemoglobin, hematocrit, and red blood cell count help determine whether anemia is present.

Does high MCH mean that I have too much iron?

No. MCH does not measure iron stores. Ferritin and other iron studies are used when a clinician needs to evaluate iron status. Do not start iron based only on an MCH result.

Are high MCV and MCH always serious?

No. Mild elevations can have reversible causes or may not require treatment. The degree of elevation, persistence, symptoms, other CBC results, and underlying cause determine its importance.

Can high MCV and MCH indicate cancer?

High MCV and MCH alone do not indicate cancer. Less common bone marrow disorders can cause macrocytosis, but vitamin deficiencies, alcohol exposure, liver disease, medication effects, and thyroid disease are among the more familiar explanations. Persistent unexplained abnormalities should be evaluated rather than self-diagnosed.

Should I take vitamin B12 or folate supplements?

Ask a clinician before treating an unexplained result. Supplementation may be appropriate when a deficiency is confirmed or strongly suspected, but treatment depends on the cause. A person with an absorption problem may need a different approach than someone whose deficiency is caused by diet.

Key Takeaways

High MCV means red blood cells are larger than the laboratory reference range; high MCH often accompanies larger cells.

The pattern is called macrocytosis and can occur with or without anemia.

Common causes include vitamin B12 or folate deficiency, regular heavy alcohol use, liver disease, hypothyroidism, medications, and reticulocytosis.

MCH is not the same as MCHC, and neither result should be interpreted alone.

A clinician may review the full CBC, previous results, a blood smear, reticulocyte count, vitamin levels, thyroid tests, liver tests, medications, and alcohol history.

Do not start iron or folic acid solely because MCV or MCH is high.

Sources

MedlinePlus: Red Blood Cell (RBC) Indices

MedlinePlus: MCV (Mean Corpuscular Volume)

American Academy of Family Physicians: Evaluation of Macrocytosis

Merck Manual Professional Edition: Evaluation of Anemia

NIH Office of Dietary Supplements: Folate Fact Sheet for Health Professionals

NHS Scotland: Macrocytosis Guidelines

This article provides general health information and is not a substitute for individualized medical advice, diagnosis, or treatment.