MCV · high result
What does a high MCV mean?
Short answer
A high MCV (macrocytosis) means red cells are larger than normal. The common causes are vitamin B12 or folate deficiency, alcohol use, liver disease, hypothyroidism, certain medications (methotrexate, hydroxyurea, some HIV and anti-seizure drugs) and a high reticulocyte count after blood loss. It can precede anemia, so it's worth explaining even when hemoglobin is normal.
Medically reviewed by Youmna DiStefano, MD · Last reviewed September 2026
What is the normal range for MCV?
- age 18+: 80.0 – 100 fL
Often reflects vitamin B12 or folate deficiency, alcohol use, or certain medications.
Full reference table, citations and testing options: MCV biomarker page.
What are the common causes of high MCV?
- Vitamin B12 or folate deficiency
- Alcohol use
- Liver disease, hypothyroidism
- Medications: methotrexate, hydroxyurea, zidovudine, valproate, some chemotherapy
- Reticulocytosis (bone marrow responding to blood loss or hemolysis)
- Myelodysplastic syndromes in older adults (less common)
What symptoms go with high MCV?
- Often none
- Fatigue, tingling, memory issues if B12-related
What do clinicians usually check next?
- Vitamin B12 and folate (methylmalonic acid for borderline B12)
- TSH and liver panel
- Reticulocyte count and peripheral smear
- Alcohol and medication review
Follow-up tests available at TestWell: TSH (Thyroid Stimulating Hormone) ($26.99), TSH + Free T4 ($27.99), Vitamin B12 ($25.99), Methylmalonic Acid (MMA) ($49.99), Folate (Vitamin B9) ($32.99).
How do you recheck MCV?
Prices are cash-pay; every order adds one $6 lab processing fee. Physician authorization is included; no insurance or referral needed.
| Test or panel | Type | Price | Fasting | Results |
|---|---|---|---|---|
| General Wellness Panel | Panel · 4 tests | $89.99 | Yes | 1–3 business days |
| Blood Clotting Panel | Panel · 4 tests | $149.99 | No | 3–7 business days |
| Baseline Anemia Panel | Panel · 5 tests | $74.99 | Yes | 2–4 business days |
| CBC with Differential | Test · 14 biomarkers | $21.99 | No | 1–3 business days |
Common questions
Is a high MCV serious?
It's a clue, not a diagnosis. Most causes — B12, folate, alcohol, thyroid — are treatable; a persistently unexplained high MCV in an older adult gets a hematology look.
Sources
Educational content, not a diagnosis. Lab results are one input; a clinician interprets them with your history and exam.