MCV (Mean Corpuscular Volume)
Complete guide to MCV testing — normal ranges, causes of microcytic and macrocytic anemia, and when to get tested.
What is MCV?
Mean Corpuscular Volume (MCV) measures the average size of your red blood cells. It helps classify different types of anemia and identify their underlying causes.
Why is it Important?
MCV is used to:
- Classify anemia as microcytic (small cells), normocytic (normal size), or macrocytic (large cells)
- Guide diagnosis of nutritional deficiencies
- Monitor treatment for anemia
- Detect alcohol abuse (elevated MCV)
Normal Ranges
| Classification | MCV Range | Unit |
|---|---|---|
| Microcytic (small cells) | < 80 | fL |
| Normocytic (normal size) | 80 – 100 | fL |
| Macrocytic (large cells) | > 100 | fL |
What Do Abnormal Results Mean?
Low MCV (Microcytic Anemia)
Common causes include:
- Iron deficiency anemia (most common)
- Thalassemia (genetic blood disorder)
- Anemia of chronic disease
- Lead poisoning
- Sideroblastic anemia
High MCV (Macrocytic Anemia)
Common causes include:
- Vitamin B12 deficiency
- Folate (vitamin B9) deficiency
- Alcohol abuse
- Liver disease
- Hypothyroidism
- Medications (methotrexate, anticonvulsants)
- Myelodysplastic syndrome
Normal MCV with Anemia (Normocytic Anemia)
Common causes include:
- Acute blood loss
- Kidney disease
- Bone marrow disorders
- Hemolysis (red blood cell destruction)
- Mixed deficiencies (iron + B12)
Diagnostic Approach
MCV is interpreted with other CBC indices:
- Low MCV + Low Ferritin: Iron deficiency
- Low MCV + Normal Ferritin: Thalassemia
- High MCV + Low B12/Folate: Megaloblastic anemia
- High MCV + Normal B12/Folate: Check alcohol use, liver function, thyroid
When Should You Get Tested?
MCV is automatically calculated in routine complete blood count (CBC). It's particularly useful when anemia is detected to determine the cause.
This information is for educational purposes only and is not a substitute for professional medical advice.
Last reviewed: 2026-02-13