Doctor's Assessment Included
Every result includes a professional assessment from a BIG-registered doctor. For treatment decisions, discuss your results with your GP.
MCV levels: what do they tell you about your health?
MCV stands for mean corpuscular volume — the average volume of your red blood cells. It is a standard component of the complete blood count and provides information about the size of your erythrocytes. Red blood cells that are too large or too small can indicate a deficiency in certain nutrients, a blood disorder, or an underlying disease. MCV is rarely assessed in isolation — it is most valuable in combination with other blood values such as haemoglobin, MCH, and ferritin.
Reference Ranges
Reference ranges may vary between laboratories. When you order a test, a BIG-registered doctor assesses your personal results in context. For treatment decisions, discuss your results with your GP.
What It Measures
This test works out the average volume of a single red blood cell. The volume of a single red blood cell is measured in femtolitres (fL). The value is derived from your hematocrit and your red blood cell count.
MCV reflects the average size of your red blood cells. It helps sort your red blood cells into smaller than normal, normal, or larger than normal. That makes the MCV value a useful starting point when looking into the cause of anaemia.
Why It Matters
MCV helps work out which type of anaemia is present. A low MCV value can point to iron deficiency, while a high MCV value may relate to a shortage of vitamin B12 or folate. Your GP looks at your blood values as a whole.
A high value means your red blood cells are larger than normal. It can be linked to liver problems or certain medications, among other things. Because of this, the result guides your GP toward the right next step.
When to Test
MCV is a standard component of a complete blood count, so it is often measured automatically. It is particularly useful when symptoms consistent with anaemia are present: fatigue, pallor, dizziness, shortness of breath, or difficulty concentrating.
If you already know you have anaemia, MCV helps identify the cause and guide appropriate treatment. With a known deficiency in iron, vitamin B12, or folate, repeated MCV measurements can show whether supplementation is having an effect.
MCV is also regularly measured in cases of prolonged excessive alcohol use, as it is one of the most sensitive markers for alcohol-related liver damage. Fasting is not required for MCV.
Symptoms
Low Levels
High Levels
In alcohol-related macrocytosis, there are often no symptoms directly linked to the MCV — the elevation is a signal of liver or bone marrow damage.
An MCV above 110 fL is significantly elevated and warrants further investigation for vitamin B12 deficiency, folate deficiency, thyroid problems, or a bone marrow disorder.
Lifestyle Tips
For low MCV due to iron deficiency, diet is an important factor. Iron-rich foods — red meat, legumes, dark leafy greens, and whole grains — help replenish your iron stores. Combine plant-based iron with vitamin C (bell peppers, citrus fruits) for better absorption. Tea and coffee with meals actually inhibit iron absorption.
For high MCV due to vitamin B12 deficiency, consider more animal products (meat, fish, eggs, dairy) or targeted supplementation. Vegans always need a B12 supplement. Folate is found particularly in green leafy vegetables, legumes, and citrus fruits.
If alcohol use is the cause of high MCV, reducing or stopping is the only effective measure. MCV typically normalises within two to four months after cessation.