Blood count and blood group · Blood

MCV

The average size of the red blood cells; helps find the cause of anemia (iron deficiency or vitamin deficiency).

At a glance

Measured in blood
In 15 test panels
No special preparation

Explanation

MCV: what is measured?

MCV (mean corpuscular volume) is the average volume of a red blood cell, expressed in femtoliters. With iron deficiency, new red blood cells become smaller than normal; with a deficiency of vitamin B12 or folic acid, they become larger instead. The MCV says little on its own; it gains meaning in combination with the hemoglobin and the ferritin, as the Dutch GP guideline (NHG) on anemia prescribes.

What can it detect?

Anemia due to iron deficiency or thalassemia (small cells, low MCV)
Deficiency of vitamin B12 or folic acid (large cells, high MCV), sometimes even before anemia is present
Regular alcohol use and some liver diseases (high MCV)

Result

What does the result mean?

MCV too high

A raised MCV means that the red blood cells are larger than normal on average. The best-known cause is a deficiency of vitamin B12 or folic acid, for example due to a stomach condition, a vegan diet or medicines such as metformin and stomach acid inhibitors. A slightly raised MCV is also often caused by regular alcohol use, liver disease, an underactive thyroid or medicines such as hydroxycarbamide, methotrexate and some antiepileptic drugs. Many young red blood cells (reticulocytes) after blood loss or with increased breakdown also make the MCV higher. With a strongly raised MCV together with a low hemoglobin and abnormal white blood cells or platelets, a bone marrow disorder may play a role; this is rare and the GP investigates it further.

MCV too low

A low MCV means small red blood cells. Together with a low hemoglobin and a low ferritin, this fits anemia due to iron deficiency, the most common cause. If the ferritin is normal, it may be carriership of thalassemia (an inherited hemoglobin disorder that occurs mainly in people with ancestors from the Mediterranean region, Africa, Asia, the Middle East or the Caribbean) or anemia due to a chronic inflammatory disease. In thalassemia carriership, the low MCV usually causes no symptoms and taking iron is of no use. A slightly low MCV with a normal hemoglobin often means nothing yet; the GP then looks at the ferritin.

After an abnormal result

With a low MCV, the GP looks at the ferritin and, with iron deficiency, treats the cause; with iron deficiency over the age of 50, examination of the stomach and bowel follows. With a high MCV, the GP usually has vitamin B12, folic acid, reticulocytes and LDH measured and asks about alcohol use and medicines. With an unexplained, strongly abnormal MCV together with other abnormalities in the blood count, the GP consults an internist (specialist in internal medicine) or hematologist.

Reliability

How reliable is the test?

The MCV is measured accurately by the blood cell counter. According to the Dutch GP guideline (NHG) on anemia, the MCV is only useful together with the ferritin for determining the cause of anemia: virtually every anemia starts with a normal MCV, and some causes give either a low or a normal MCV. A normal MCV therefore does not rule out iron deficiency or a vitamin deficiency, especially not when both are present at the same time.

What can affect the result?

A combined deficiency (for example iron and vitamin B12) can cancel each other out, so that the MCV appears normal.
After a recent bleed or with increased breakdown of red blood cells, the young cells (reticulocytes) temporarily raise the MCV.
Alcohol use, liver disease, an underactive thyroid and medicines such as methotrexate, hydroxycarbamide and antiepileptic drugs raise the MCV without a vitamin deficiency.
Blood that is in transit to the laboratory for a long time (more than a day, especially in warm weather) makes the cells swell, so that the MCV comes out slightly higher.

Who it is for

Who is the test useful for?

Useful for

Useful as part of the blood count when anemia is (suspected to be) present, with a vegetarian or vegan diet, with stomach or bowel diseases, with regular alcohol use and in people from a risk group for thalassemia. Apart from the hemoglobin and the ferritin, the MCV has little value; it is a supporting value, not a test on its own.

How common is it?

In general practice, anemia is diagnosed in about 9 in 1000 people per year; in half of them iron deficiency is the cause (low MCV), and in about 2 in 1000 per year a deficiency of vitamin B12 or folic acid (high MCV). An estimated 1 in 100 Dutch people is a carrier of a hemoglobin disorder such as thalassemia, which gives a low MCV without iron deficiency.

Dutch GP guideline (NHG) on anemia (M76)

Drawbacks and risks

A slightly abnormal MCV with a normal hemoglobin is usually harmless, but without the other values it can lead to unnecessary worry or unnecessary iron use.

Get tested

MCV: test panels

MCV is part of these test panels. You order online and have your blood drawn at a collection point or collect the sample at home.

Blood draw
General Health Checkup
With this General Health Check-up, you gain detailed insight into your overall health and well-being.
€ 125,00
Blood draw
Blood Count
Blood Count; complete analysis of blood cells for detection of anemia and infections.
€ 19,00
Blood draw
Complete Blood Count (CBC)
Complete Blood Count Extended; standard blood count plus detailed white blood cell analysis.
€ 27,00
Blood draw
PhenoAge
PhenoAge Biological Age Test; determine your biological age with 9 standard blood values.
€ 85,00
Blood draw
InsideTracker
InsideTracker Blood Analysis: analyze 48 biomarkers for complete health optimization and personalized recommendations.
€ 335,00
Blood draw
Endurance Sports
Complete blood count, iron status (ferritin, transferrin), kidney function, liver function, testosterone, and hs-CRP. For athletes and endurance sport participants.
€ 203,00
Blood draw
General Blood Test (Basic)
Hemoglobin, MCV, TSH, fT4, eGFR, creatinine, ALT, AST, sodium, and potassium. General health check of kidney, liver, and thyroid.
€ 125,00
Blood draw
Comprehensive Blood Test
Comprehensive blood test covering blood count, thyroid, kidney and liver function, glucose, inflammation markers and cholesterol.
€ 215,00
Blood draw
Fatigue Basic
Vitamin D, B12, TSH, fT4, glucose, hemoglobin, MCV, iron, and magnesium. Tests most common causes of fatigue.
€ 116,00

How reliable is the test?

MCV