MCV in a blood test. What is it, the norm and deviations in children, women, men

A detailed blood test allows you to evaluate not only quantitative, but also qualitative indicators of its components, which makes it possible for the doctor to get the most complete picture of the state of the body. When referring a patient to this examination, the specialist, relying on the present symptoms, can choose several parameters from all the parameters available for study, although their total number reaches at least 20.

But whatever his choice, the MCV value will always be among the indicators noted for the study. What is MCV in a blood test and why is its study an integral part of this laboratory diagnostics? Translated from English, the abbreviation stands for Mean Cell Volume, which means "average erythrocyte volume."

What does MCV show on a complete blood count?

Red blood cells, called erythrocytes, can normally vary in number and shape. But at the same time, in a healthy body, most of them should be correct, taken as a normal form. This is directly related to the functional ability of erythrocytes, that is, a healthy cell - normocyte is fully involved in the transfer of oxygen to the tissue structures of the body. And after destruction, it will be replaced by the same efficient erythrocyte.

In the event that the shape of the erythrocyte is changed, and it is an ovalocyte, macrocyte, microcyte or schistocyte (a fragmented helmet cell), there may be certain difficulties with transporting oxygen. This heterogeneity of red blood cells can cause other adverse effects. Therefore, in many situations, when making a diagnosis, data are used not only from a general blood test, but also from a detailed one - which allows you to assess in detail the characteristics of each group of cells - erythrocytes, leukocytes, platelets and their varieties.

MCV values ​​are calculated by dividing the total blood cell volume by total number erythrocytes. The formation of cells of an altered shape is called heterogeneity, and this condition leads to deviations from the generally accepted norm. If the MCV in the blood test is low, such cells are called macrocytes, and if the erythrocytes are characterized by a decrease in volume, then they are called microcytes.

Normal erythrocyte and varieties of pathologically altered cells

This indicator can be calculated in two quantities - cubic micrometers (μm 3) and femtoliters (fl). When conducting diagnostics in the laboratory, it is automatically measured by the analyzer. In the blood test, in addition to MCV - the average volume of red blood cells, several more values ​​\u200b\u200bare measured that characterize these blood cells. This:

  • RBC - information about the number of red blood cells;
  • MCH (color indicator) - makes it possible to determine the average amount of hemoglobin contained in each individual erythrocyte;
  • MCHC - shows the average amount of hemoglobin contained in all red blood cells in the human body;
  • RDW-CV - provides information on the width of the distribution of erythrocytes;
  • Hematocrit (HCT or Ht) is the percentage of the volume of red blood cells with the rest of the blood cells.

In some cases, in the presence of symptoms of joint damage or aggravated rheumatoid heredity, it is recommended to take a blood test for anti-MCV. This study is not particularly relevant to the study of the qualitative and quantitative characteristics of erythrocytes. It is carried out to detect antibodies to citrullinated vimentin, a protein used for diagnosis rheumatoid arthritis. An increase in anti-MCV levels in the blood is observed 10–15 years before the onset of overt symptoms of the disease.

Therefore, if the interpretation of the obtained blood test materials indicates that the level of anti-MCV is elevated, the rheumatologist must take this into account. First of all, the patient needs to be explained the importance of regular blood donation for a general and detailed analysis of its components, and they must include an anti-MCV indicator.

One study of the latter value is not enough to understand the overall picture of the patient's condition, and complex diagnostics will allow you to recognize the onset of the disease in time and take appropriate measures.

Normal performance

Permissible limits of values, defined as the MCV norm in a blood test, change in a person throughout life. In addition, some factors may affect the results of the examination, for example, a large breakfast, laboratory inaccuracies, the use of drinks containing alcohol, the use of antidepressants, or hormonal drugs.

In children under one year old, 71-112 fl are considered normal values, and newborns have the most high performance for childhood. However, with the growth and development of a child, the level of MCV gradually decreases to the levels taken as the norm in an adult. Further, as the organism grows older, the normative values ​​increase again. It is noted that the MCV norm in women is slightly higher than in men.


MCV Norms - Children and Adolescents

Why might the MCV increase?

In many cases, the deviation of this indicator from the permissible limits means the presence and development of a pathological process, and timely identification of the problem gives a chance for a quick and effective cure. The risk group includes patients with a hereditary predisposition to blood diseases and people leading an inactive lifestyle, as well as those who do not adhere to proper nutrition.

There are other reasons leading to an increase in the average volume of erythrocytes. These include:

  • intoxication with medications - antibiotics, sulfonamides, etc.;
  • anemia that develops as a result of significant blood loss and the death of red blood cells;
  • food poisoning, infectious diseases gastrointestinal tract, liver pathology;
  • autoimmune diseases characterized by changes in cellular development;
  • deterioration in the quality of functioning thyroid gland with iodine and iron deficiency;
  • hormonal imbalance caused by the use of contraceptives made on the basis of hormones;
  • endocrine disease- myxedema and various pathologies of the bone marrow;
  • activities in hazardous industries, leading to constant contact with poisons and toxins.

An increase in MCV levels may be due to a lack of vitamin B 12 due to a lack of cobalt-containing substances in the body. In this case, there is a decrease in the proportion of erythrocytes, but their size increases significantly.

A slight rise in values ​​may be observed in heavy smokers. Alcohol abuse, as a rule, always provokes the occurrence of macrocytosis, but hemoglobin values ​​remain unchanged and do not leave the normal range.

Such a feature at laboratory research always allows to diagnose alcoholism. The macrocytosis caused by such a factor is a reversible process, and after about 2 months of abstinence from the use of alcohol-containing products, the MCV indicator returns to normal.

Reference! Some experts believe that taking antidepressants can increase the average volume of red blood cells, but so far this assumption has no conclusive evidence.

An increase in MCV is usually characterized by certain symptoms, such as general pallor, palpitations, which is determined even at rest. Also, patients voice complaints of abdominal pain of unknown etiology, and they have a slight jaundice. skin, especially the nasolabial triangle. Such signs are the reason for visiting a doctor and taking a blood test.


Normal MCV in Adults

Reasons for declining levels

The factors leading to a decrease in the average volume of erythrocytes include the use of medications, such as antimicrobial, sedative, antiviral, and others. At the same time, tissue structures internal organs are deficient in essential nutrients. If the blood test showed that the level of MCV is low, this means that it is possible is developing a certain number of pathological conditions.

Lowering the values ​​of the average volume of erythrocytes below the norm is observed with microcytic and hypochromic anemia, provoked by a violation of the formation of hemoglobin. And as you know, hemoglobin has a direct impact on the size and appearance of red blood cells, and if the content of this protein in the blood is lowered, then the cells will differ in smaller volume. Also, the pathology of hemoglobin synthesis is characteristic of thalassemia, a genetic blood disease.

Another important reason for the decrease in MCV indicators can be called a violation of the water-electrolyte balance, in which the lack of fluid causes a decrease in all its containing cellular spaces. In this case, we are talking about hypertonic dehydration or dehydration of the body, due to the loss of hypotonic fluid and insufficient water intake. In addition to the above factors, a decrease in the average volume of red blood cells to this condition can lead to intoxication of the body with lead ions and the development of malignant oncological processes.

It is also caused by such a hereditary disease as Porphyria, characterized by pathological synthesis of hemoglobin. At low MCV values, patients complain of weakness, fatigue, excessive fatigue. At the same time, increased irritability, absent-mindedness, impaired memory and concentration are noted. All these manifestations, taken together or some of them, are a weighty argument for visiting a doctor and taking a blood test.

Given that the MCV and its normative values ​​change with a person's age, the results of a blood test should only be interpreted by a qualified professional. An increase or decrease in values ​​in most cases indicates pathological changes activities of organs or systems of vital activity. Therefore, in order to establish the final diagnosis, additional diagnostic methods will be required and a blood test may be repeated.

An indicator such as MCV in a blood test was not always available to a practitioner. Its study became possible with the widespread introduction of hardware analysis methods, and it is automatically issued when a certain amount of blood is loaded into a biochemical analyzer.

Previously, almost throughout the 20th century, the MCV indicator in the blood test was not taken into account, since there were no such methods. It was only possible to estimate the size of erythrocytes under a microscope, which was laborious and subjective. Of course, when deciphering a blood test, doctors necessarily took into account the size of blood cells, but it was impossible to estimate this indicator - the average volume of red blood cells - for each blood cell.

MCV in a blood test - what is it?

MCV in a blood test, or the average volume of erythrocytes, is some average indicator that more or less likely reflects the volume of a red blood cell. He does not possess high information content, and cannot accurately say what pathological processes occur in the body. Translated from English, MCV in a blood test, or Mean Cell Volume, means the average volume of an erythrocyte.

This indicator refers to the so-called erythrocyte indices, these indices allow you to determine the main characteristics of red blood cells. Also, these indices include such well-known studies as the determination of the average content of hemoglobin in the cell, which has now replaced the routine determination of the color index.

Of course, if we take each individual blood transport cell, we will see that its volume is within limits close enough to this value, since the average volume of erythrocytes is a median value. There are necessary conditions under which the results of this analysis can be taken as true, namely: with normal, mature red cells with approximately the same volume.

In the event that the general blood test is represented by erythrocytes of different shapes, or different sizes, that is, in the presence of a, then such an indicator as mcv analysis will be of very low value, since the mean volume of erythrocytes cannot be reliably calculated. This analysis in laboratory practice can be used for differential diagnosis, and will help identify the causes of deviations.

It should be said that cellular red indices can only speak about red blood: about the iron content in the patient's body and about the presence or absence of hypoxia of organs and tissues. The average volume of erythrocytes - MCV, does not tell us anything about leukocytes, blood coagulation, platelets, and it is not even possible to evaluate some simple indicators, for example, using this index.

Reference or normal values

Normally, in men and women, on average, it is 80 fl, or femtoliters. This is a very small value that is never used in our everyday practice. For comparison, it can be pointed out that this volume is as much less than a drop of water, how many times a drop of water is less than a full tank in the form of a cube with a side of 5 meters, a volume of 125 cubic meters, the water in which weighs 125 tons.

If we talk about age-related changes, then the largest cell sizes, and, consequently, their volume, exist in newborns and in children of the first month of life. At this time, erythrocytes are finally freed from fetal hemoglobin, and they switch to new hemoglobin.

Normal adult hemoglobin works more efficiently with air gas exchange in the lungs, and red blood cells with a smaller volume are able to perform the same full-fledged function. Also in old age, and even from the age of 45, our oxygen carriers have a large amount of volume. Therefore, it is possible to construct a certain curve, where the norm of the average volume of erythrocytes in adults is slightly lower than in the extreme age limits.

Normal values ​​in children are shown in the following table:

Then the decline begins to level off, and children from 10 to 12 years old have general indices, from 76 to 90 fl. We have already mentioned the normal level of the average volume of erythrocytes in adults, and detailed information can be found in any laboratory reference book. It is only worth mentioning that the level of hormones and sexual dimorphism makes a small difference, but not more than 1% of the existing values.

In mature and old age, the MCV index in the blood test rises again. This indicates a compensatory adaptation of red blood to the existing processes of atherosclerosis, increasing hypoxia, the appearance of chronic non-specific lung diseases and a general decrease in the respiratory surface of the alveoli. The average value of 65 years and older is from 82 to 102 fl.

Some Reasons for Decreasing and Raising Values

Reduced values

Consider under what conditions the MCV norm can be violated, and what are possible reasons deviations, what can they tell the doctor and the laboratory assistant about the state of human health?

First of all, you need to understand that low values, at which the indicator is below 80 fl, can be interpreted unequivocally as a disease, since there is not enough hemoglobin in the erythrocyte. In the same case, if the volume increases, then this does not always indicate a disease, it can be, as in the case of the age norm, a compensatory reaction to the changed conditions of existence.

The main reasons for lowering the values ​​are:

  • iron deficiency anemia, in which there is a lack of iron in the body;
  • secondary chronic diseases leading to anemia: the pathology of both the red bone marrow and the presence of chronic blood loss, for example, with dysfunctional uterine bleeding;
  • hereditary blood diseases - thalassemia, hemoglobinopathies;
  • hyperthyroidism.

It is on the basis of this index that a blood test suggests the classification of anemia into normocytic, macrocytic and microcytic. Here we are talking about erythrocyte hypochromia. The laboratory doctor no longer has to tediously examine a smear under a microscope and visually compare the cell size with standard values. With a decrease in the volume of erythrocytes, microcytosis occurs, which is recorded by the device.

Increased values

An increase in MCV, in which red cells have a volume value of more than 100 fl in adults, and more than 105 fl in the elderly, occurs for the following reasons:

  • decreased thyroid function, hypothyroidism or myxedema;
  • chronic liver disease, gastrointestinal tract leading to the development of folic acid deficiency anemia;
  • aplastic anemia and similar damage to the bone marrow, for example in cancer patients, as well as in patients on immunosuppressive therapy;
  • B-12 deficiency anemia leading to megaloblasts - increased sizes of blood cells;
  • various types of autoimmune anemia.

Finally, a long history of smoking and drinking alcohol also leads to endogenous intoxication and beriberi, which can manifest as macrocytosis, that is, an increase in the size and average volume of red blood cells. In this case, there may also be a decrease in the level of red blood cells, or anemia develops.

Do not think that anemia is manifested only by a decrease in the level of cell volume. Anemia is an insidious group of diseases of different etiologies and different mechanisms of origin, but they have one thing in common: in any case, they manifest as chronic hypoxia of organs and tissues.

In conclusion, it should be noted that in case of acute anemia, the definition of the above indices does not make sense, due to the lack of information content. After all, with acute bleeding, neither the volume nor the shape of the erythrocyte will change. The study of this indicator allows you to identify only chronic diseases in which the production of healthy red blood cells is somehow impaired, and at the same time there may be no symptoms.

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Having heard from a doctor that the average volume of erythrocytes is lowered, the parents of a sick child or an adult patient wonder what it is. A technique for conducting such an analysis has recently appeared.


Normal values

A complete blood count contains the MCV value, or the average volume of red blood cells in the blood. If the MCV is low, then the size of the red blood cells is also below normal.

Doctors judge the norm or decrease in the volume of red blood cells rather conditionally. The size of the red blood cell changes even during the day due to physiological reasons: after work, in a tired person, blood cells increase, and after rest they become smaller. At 8 o'clock in the morning, when most tests are performed, the size and volume of the bodies reaches a minimum.

The volume of red blood cells and their size in an adult is determined in femtoliters (fl) or microns. Normal values ​​change throughout life. In middle age (40-59 years) they fluctuate between 80-100 fl in a woman and 81-94 fl in a man. The indicators in younger patients differ slightly (a little more), therefore, 80 vials are most often taken as the average rate. In men over 65 years of age, the norm may vary between 78-103 fl.

Erythrocytes with a normal volume are called normocytes, while those with low and high volume are called micro- and macrocytes, respectively. The size of the cells is regulated by the body itself, depending on their number in the blood: if there are a lot of red blood cells, then the MCV is lower.

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21.10.2019

Norm in a child

In the first month of life in children normal size erythrocyte is more than 105 fl. By six months, this value decreases to 90, and by 1 year - to 78-80 fl. This is a normal physiological process during which fetal hemoglobin is replaced with a new one that adults have. At 5-12 years old, the average volume indicators again slightly increase (up to 89 units), but by the age of 18 they reach the norm of an adult.

Why MCV is lowered

If the MCV in the blood test is low (does not reach the prescribed 80 fl), most often this indicates that the child or adult develops some form of anemia, i.e., a lack of hemoglobin in red blood cells. Due to the compensatory properties of blood, the number of red blood cells themselves may increase, but all of them will poorly supply oxygen to the tissues and organs of a sick person.

The reasons for the decrease in the average volume of erythrocytes may be in the following conditions and pathologies.

A general blood test determines a number of its characteristics that allow a specialist to assess the patient's health status. One of its key indicators is MCV in a blood test. We propose to consider what is hidden under this designation and why you need to diagnose it.

What is MCV in a blood test?

MCV is the average volume of erythrocytes (erythrocyte index), which allows you to determine the state of these blood cells in humans. Erythrocytes are blood cells that give blood its red color. They are characterized by the shape of a biconcave disc and the absence of a nucleus. On their surface is hemoglobin, a protein that transports oxygen from the lungs to tissues and organs, and from them back to the lungs. Erythrocytes play a very important role in all processes that occur in human body. A change in these characteristics indicates the development of allergic reactions, inflammatory processes, deficiency of vitamins and trace elements.

In the body of a healthy person, the composition of blood cells is constant, due to which their parameters, number and size are maintained at the same level. In the event of any pathology in the body, these indicators change.

As a rule, MCV is determined in a clinical (general) blood test, but in some cases a separate study may be performed on the patient to identify this characteristic.

The mean erythrocyte volume can be calculated by dividing the sum of the cell volumes by the total number of erythrocytes in the blood. The MCV unit is femtoliters (fl, fl) or microns 3. This blood count is used to diagnose various kinds anemia (low level of hemoglobin in the blood), since each type of this disease requires the appointment of a specific therapy.

Normally, the values ​​of the average erythrocyte volume will depend on the age of the person.

Consider the values ​​of the MCV norm in a blood test, in fl:

  • children up to 14 days of life - 88-140;
  • children under 1 month - 90-111;
  • children under 2 months - 83–106;
  • children under 4 months - 75-96;
  • children under 6 months - 66-85;
  • children under 9 months - 68-86;
  • children under 1 year old - 72–84;
  • children under 5 years old - 72–85;
  • children under 10 years old - 73–86;
  • children under 12 - 75–93;
  • children under 15 - 76–95;
  • boys under 18 - 75-94;
  • girls under 18 - 77-98;
  • men under the age of 45 - 82-98;
  • women under 45 - 83-100;
  • patients under 65 years old - 80–102;
  • men after 65 years - 82–103;
  • women after 65 years - 80-102.

Abnormal MCV in the patient's blood test gives the doctor reason to diagnose the presence of such forms of anemia as microcytic, normocytic or macrocytic.

A decrease in MCV in a blood test indicates the development of microcytic anemia, which can be caused by:

  • deficiency of iron in the blood;
  • the presence of chronic diseases;
  • the development of malignant neoplasms;
  • thalassemia (a disease in which the production of hemoglobin in the blood is reduced);
  • hereditary diseases;
  • lead poisoning;
  • taking certain medications;
  • alcoholism.

According to the decoding of a blood test for MCV, a high level of this indicator accompanies macrocytic types of anemia and other pathologies, in particular:

  • megaloblastic anemia resulting from protein deficiency;
  • malignant hereditary anemia;
  • pancreatic insufficiency;
  • bowel disease;
  • toxic or drug poisoning;
  • malabsorption of vitamin B12;
  • hypothyroidism;
  • liver disease.

As for normocytic anemia, there are such types of them as:

  • hemolytic;
  • hepatic;
  • renal;
  • posthemorrhagic;
  • aplastic;
  • anemia caused by diseases of the endocrine system.

In addition to the possibility of differentiating the type of anemia, the indicator of the average volume of an erythrocyte makes it possible to assess the development of water and electrolyte balance disorders in the patient's body. A decrease in MCV in a blood test is a sign of the hypertonic nature of these disorders, and its high rates are associated with their hypotonic nature.

Erythrocytes, like other elements of the blood, perform their functions in the body. Red blood cells are responsible for supplying organs with oxygen and carbon dioxide, transporting enzymes, lipids and amino acids, regulate acid-base balance, adsorb toxins and antibodies, and participate in the dissolution of blood clots. Any significant changes in their qualitative and quantitative characteristics signal pathological processes.

The morphological parameters of these elements are evaluated using such calculated values ​​as erythrocyte indices. One of them is MCV. So in a blood test, the average volume of red blood cells is indicated, and it is measured in femtoliters or cubic micrometers, respectively - fl or micron³.

MCV is one of the indicators of the state of red blood cells and is determined during a general analysis. It allows you to get more accurate and objective results regarding the volume of erythrocytes, compared with a visual assessment during a conventional microscopic examination. It is calculated by dividing the hematocrit value (the volume of blood per erythrocytes in 1 mm³) by total number erythrocytes. The value of the average volume will not be reliable with a large number of red cells with different sizes and different shapes.

Norm

MCV is not a constant value, changes with age and depends on gender. The maximum normal value of the average volume of red cells is observed in newborns - 90-140 fl. By one year, MCV changes to 71-84 fl, in the period from 5 to 10 years it is 75-87 fl. At the age of 15-18, the volume of erythrocytes in women reaches 78-98 fl, in men - 79-95 fl. From 18 to 45 years old - 81-100 fl in women, 80-99 fl in men. From 45 to 65 years - 81-101 fl in women and men. At the age of 65 years, the MCV norm is from 81 to 103 fl.

If the erythrocytes in the analysis are normal, they are considered normocytic, with a value below 80 fl, the state is called microcytosis, if the MCV is above 100 - macrocytosis.

Purpose of analysis

With the help of MCV, differential diagnosis anemia. This indicator is important for the doctor, because it confirms the hematological problem and allows you to find out the type of anemia.

In addition, the development of water and electrolyte imbalance in the body is determined by the average volume of red blood cells. If the red blood cells are low, this may indicate dehydration (hypertonic dehydration). If they exceed the norm, this indicates another type of dehydration - hypotonic.

Deciphering the analysis

Deciphering the result of a blood test is the responsibility of the attending physician. If the MCV is elevated or lowered, this makes it possible to assume the presence of any diseases. In this case, re-analysis and other examinations are prescribed.

Based on the MCV value that erythrocytes have, different types of anemia are distinguished: normocytic, microcytic and macrocytic.

Modern blood analyzers give a more accurate and objective result than a study under a microscope

If MCV is within the normal range, we are talking about the development of normocytic anemia, which include the following:

  • hemolytic,
  • aplastic,
  • hemorrhagic,
  • anemia in liver disease,
  • hepatic,
  • anemia in endocrine pathology.

If red blood cells have an increased average volume, this indicates macrocytic anemia and other pathologies, including:

  • vitamin B12 deficiency;
  • folic acid deficiency, megaloblastic and pernicious anemia;
  • hypothyroidism;
  • bowel disease;
  • liver disease;
  • reduced function pancreas;
  • bone marrow diseases;
  • drug intoxication;
  • alcoholism.

The average volume of red blood cells may increase slightly in smokers and in women taking hormonal contraceptives.

If the MCV is low, then this indicates microcytic anemia, which are caused by the following factors:

Video about the types and symptoms of anemia:

Conclusion

MCV in the analysis allows a more accurate determination of the average volume of red cells, in contrast to studies under a microscope. The diagnostic value of this indicator lies in the ability to differentiate different anemias.