Average volume of red blood cells in a child. The average volume of red blood cells is reduced: reasons

Using the MCV blood test indicator in a child, knowing its norms and interpretation, you can determine the quantity, quality and level of red blood cells. And also based on the results of this test, various diseases are determined. This analysis is done in laboratory conditions using clinical blood sampling, which can be taken from a vein or finger. By decoding the analysis it is established accurate diagnosis and type of anemia.

Diseases in different people various. And first of all, when a person gets tested, they look at the number and general state erythrocytes in the blood. After all, it is they who, with the help of hemoglobin, transport oxygen and carbon dioxide. If red antibodies are detected, then it is necessary to identify a disease of a hematological nature as soon as possible, and even more so if it concerns the body of children.

MCV in a blood test is the average number of red blood cells, the so-called red blood cell index. Thanks to this ratio, the general condition of all red blood cells is determined. Also MCV blood test is reliable indicator when identifying various pathologies. Red blood cells are the main indicators of health for an adult and even more so for a child. If changes in red blood cell parameters are diagnosed in the blood, this is evidence that the body goes inflammatory process or there is an allergy, a possible deficiency nutrients, necessary for a person for a full existence.

If a person is healthy, then there is such a thing as the norm of red blood cells in the blood. And if this norm changes upward or downward, this is an indicator of the development of pathology, which is fraught with dangerous diseases.

This is why a normal volume of red blood cells is so important for a child. After all, these blood bodies take part in most metabolic processes.

Child indicators for analysis

There are two main reasons why MCV analysis should be performed:

Disturbances and changes in water-salt balance. This happens as a result intestinal infections, acute respiratory viral infections and acute respiratory infections.
Recognition and study of anemia. This is a lack of iron in the body.

Other important indications for analysis are:

hormonal disruptions;
metabolic disease;
prerequisites for obesity;
diabetes;
low immunity.

This analysis helps to identify different types anemia: normochromic, macrocytic and microcytic.

Normochromic is anemia that develops due to illness bone marrow. This manifests itself when chronic diseases.

Macrocytic – this type occurs due to growing red blood cells. This occurs due to a lack folic acid and vitamin B.

Microcytic - develops due to iron deficiency. There is a decrease in the synthesis of polypeptide chains.

Methods for performing MCV analysis

MCV analysis for an adult and a child is determined during a general clinical blood sample. Blood can be taken from a vein, but for a child it is better to take it from a finger. Blood sampling must be carried out following the basic rules:

the person taking the test should not drink or eat 3 to 5 hours before blood sampling;
the fence is taken (if it is a woman) in the absence of menstruation;
if an adult or child feels well, there are no complaints of malaise, chills, fever, cough.

The best time to carry out this analysis is in the morning or before lunch, when all organs are functioning most actively.

The blood that was taken for analysis is used to make a so-called smear. Then isolate required values. The average volume of red blood cells is determined by finding the sum of the number of cells per general content erythrocytes in the blood. Femtoliters are a unit of measurement called MCV (fl) or µm3.

MCV analysis results and their interpretation

The existing MCV index in a blood test is special, since it has the prerequisites for change depending on a person’s age. This index has the most great importance in newborns. Its value is 140 fl. But over time, as the child ages, this figure decreases. And when the child reaches 18 years of age, the MCV analysis value is normal. The acceptable MCV value for an adult is a figure equal to 80 - 100 fl. If we summarize all of the above, it should be noted that an MCV index value of less than 80 fl is considered underestimated, and a value greater than 100 fl is considered increased. The normal average volume of red blood cells indicates that the cell is normocytic.

Deviation from the norm and consequences

You should know that the MCV of erythrocytes in children depends on a large number of factors. If there is a deviation (decrease) given value, this condition is called microcytic anemia.

Causes of microcytic anemia:

iron deficiency;
chronic diseases;
prerequisites for the development of malignant diseases;
thalassemia – poor production of hemoglobin;
hereditary diseases;
lead poisoning;
taking certain medicines;
alcoholism.

When the volume of red blood cells decreases, the following signs are observed:

rapid fatigue;
irritability;
inattention;
absent-mindedness;
Memory is bad.

When the child is in the womb, for him to be sufficiently and normal development, as well as the formation of all its organs, a sufficient supply of iron is necessary. The child consumes it and absorbs it from the mother's body. Therefore, the risk of developing microcytic anemia is very high and thereby affects the baby’s health.

In cases where an increase in the MCV index is observed, it should be considered that this is macrocytic anemia.

Causes of macrocytic anemia:

megaloblastic anemia – a consequence of a lack of protein in the body and vegetarianism;
hereditary anemia with malignant consequences;
pancreatic function is weak;
vitamin B12 is poorly accepted by the body;
diseases of the gastrointestinal tract;
poisoning with toxins, drugs;
liver diseases;
hypothyroidism.

As a result of this condition, the child may experience chronic fatigue, irritability, absent-mindedness.

It should also be noted the reasons why an increase in the MCV index can be determined:

Very pale color lips;
abdominal pain, frequent and without reason;
V calm state tachycardia is observed;
yellowish skin.

If we're talking about about an adult, for example, a woman, then the index may be slightly higher than normal due to the use of hormonal contraceptives. Smoking also causes an increase in analysis.

There is also normocytic anemia.

Types of normocytic anemia:

hemolytic;
posthemorrhagic;
hepatic anemia;
renal anemia;
anemia, which is caused by the endocrine system;
aplastic anemia.

Despite the above data, there is still a pathology that directly depends on the level of red blood cells. This disease is called anisocytosis - a change in the size of red blood cells - and at the same time the blood is very densely populated with cells of various sizes.

As a rule, the patient is only concerned about the deviation from the norm indicated on the analysis form. And few people think about what is hidden behind the mysterious abbreviation MCV, what it means and what the hematological indicator indicates. It is worth considering the standards and possible deviations to understand under what conditions of the body the average volume of red blood cells is reduced.

Perhaps we should recall long-known facts:

red blood cells contain hemoglobin (hb);
red blood cells carry oxygen;
the amount of hb determines how firmly the cell will hold the oxygen molecule, transporting it to the tissues;
The hemoglobin content in a cell affects its size.

Determining MCV in an analysis is one of the ways to diagnose the performance of an erythrocyte.

The average volume of an erythrocyte gives a reliable picture of the functionality of the cell and often serves as the main parameter for differential diagnosis anemia. Errors in the study are possible only if the structure of erythrocyte cells is abnormal ( sickle anemia), in this case, in addition to MCV, the value of MCH and MCHC is additionally taken into account in the blood test.

Indications for use

MCV in the analysis is determined to clarify the composition of the blood under the following conditions:

metabolic disorders (changes in ion balance in cells);
hemolytic abnormalities (anemia);
hemoglobinopathies (the synthesis or breakdown of hemoglobin molecules is impaired);
myeloblastic syndrome (develops when the synthesis of red blood cells is impaired or when cells of different sizes are produced);
causeless decrease in immunity;
hormonal imbalance;
metabolic disorders.

In addition to diagnosing diseases, indications for an MCV blood test include:

routine medical examination;
liver pathologies;
preparation for surgery;
undergoing chemotherapy;
presence of blood disease in close relatives;
leukemia.

Under the influence toxic substances(chemotherapy), with illness, the number of MCV in the analysis will decrease or increase. Based on changes in laboratory data, the doctor determines the nature and severity of pathological process.

Generally accepted standards

The average MCV rate for adults: 80-100 femtoliters - such a red blood cell is considered normal.

If the numbers are below normal, then microcytosis is diagnosed.
If the result exceeds the specified value, then macrocytosis develops.

The average volume of red blood cells in the blood is not constant; it changes throughout a person’s life. Below is a table of normal reference values for boys and girls under 12 years of age.

In adolescents during puberty and in adults, MCV in a blood test depends not only on age, but also on gender.

As can be seen from the tables, MCV in the analysis changes slightly and almost always fits into the average norm of 80-100 fl.

In pregnant women, many hemolytic data change during pregnancy, but the size of red blood cells remains the same. Deviation from generally accepted norms indicates a pathology of pregnancy.

Reasons for the downgrade

There are many reasons why the average volume of red blood cells is reduced:

dehydration (with diarrhea, vomiting, large burns);
hypertensive dehydration (infusion of large amounts of saline solutions);
anemia due to hb deficiency (hypochromic, microcytic);
hemoglobinopathy;
some congenital diseases blood (thalassemia);
poisoning with metal salts (mercury, lead);
pathology of hematopoiesis (MCV is lowered due to irregular shape or smaller size of red blood cells).

A decrease in the volume of red cells is always a sign of disease. If a person feels well, but the average volume of red blood cells is reduced, this indicates a hidden course of the pathological process.

Reasons for the increase

Any deviation from the norm indicates the development of a pathological process. An increase can be caused by the following conditions:

hemolytic anemia;
vitamin deficiency (lack of vitamin B12 and folic acid);
myelodysplastic syndrome (dysfunction of the hematopoietic germ);
excessive blood loss (the increase is due to the fact that erythrocyte cells appear in the bloodstream to provide tissues with oxygen big size and at the same time general low red blood cells are diagnosed);
hypotonic dehydration (reducing the amount of salts in the plasma);
kidney pathologies associated with increased permeability of renal nephrons);
liver diseases;
endocrine disorders;
taking certain substances (oral contraceptives, alcoholic drinks);
smoking.

Macrocytosis caused by medications, alcohol, or smoking has favorable course, and after stopping taking these substances it is restored normal indicator.

An increase is no less dangerous than a decrease. Large cells do not move well through the capillaries, so when taking blood from a finger, anemia may be mistakenly detected. When the distribution of red blood cells by volume is reduced, with a normal indicator for venous blood there may be a deficiency in small peripheral vessels.

Is it possible to get a false promotion?

In laboratory practice, there are cases when the average volume of erythrocytes is increased, but no signs of hidden pathology have been identified. A false elevated result occurs in the following situations:

Ketoacidosis in diabetes. In this condition, the number of red blood cells increases, and when reacting with reagents in an electronic analyzer, a false positive result may occur.
Cold agglutination (gluing) is possible when previously frozen and poorly warmed material is used for research. Because of the cold, red blood cells stick together, and electronic equipment analyzes the resulting lump as one large cell.

A false increase makes diagnosis difficult, so before deciphering laboratory data, the doctor always clarifies what kind of blood was tested (fresh or after long-term storage). If a distortion of the result is suspected, the patient is prescribed a repeat blood donation.

A few words about anisocidosis

Not all red blood cells healthy person have the same size. Normally, the bloodstream should contain:

macrocytes – 15%;
normocytes – 7%;
microcytes – 15%.

Slight increase the percentage in favor of normocytes is considered normal and does not cause concern, but if the content of microcytes and macrocytes increases, the following symptoms may develop:

weakness;
fast fatiguability;
tachycardia and arrhythmia;
feeling of lack of air;
chest pain;
impaired sensitivity of the skin of the extremities (numbness or tingling sensation).

In severe cases, the symptoms of anisocytosis are similar to those of chronic heart failure.

Pathology is diagnosed by mechanical counting of erythrocyte elements in a blood smear. At simultaneous increase macro- and microcytes against the background of a decrease in normocytes, the electronic analyzer can show the norm. A large appearance of cells of different sizes can be provoked by:

liver pathologies;
iron deficiency;
splenectomy;
erythrocyte sludge (gluing together several elements);
beta thalassemia.

Anisacidosis has a favorable prognosis and when provoking factors are eliminated, the erythrocyte formula is restored independently, without additional therapy.

MCV in a blood test is one of the indicators of gas exchange in the body, and it is not recommended to ignore detected deviations. It is important to remember that red blood cells that are too large or too small cannot fully deliver oxygen molecules to the cells and an ischemic process develops in the tissues, which negatively affects the functioning of systems and organs.

Almost every person, with thorough examination, one or another disorder can be detected in blood cells, and this is especially true for red blood cells.

Erythrocytes are red blood cells responsible for transporting oxygen from the lungs to the internal organs.

There is a certain amount of them in the blood (on average, the norm is about 4x10^9 cells). All of them participate in the process of gas exchange between external environment and organs (through lung tissue).

Their level can be increased as a result physiological characteristics(carrying a child, living in the mountains) and decrease (if their number is reduced, then some pathological process is taking place).

In order to perform their function normally, red blood cells must have sufficient quantity hemoglobin - a binding transport molecule. It is found in every red blood cell, and its amount can be determined by measuring the average volume of red blood cells.

What is the volume of red blood cells and hemoglobin, how is it measured in adults and children, and what reasons can lead to a change in its quantity?

What is this indicator?

The term average erythrocyte volume is understood as an indicator reflecting the hemoglobin content in human erythrocytes (denoted by the abbreviation MCV). It is calculated by multiplying the hematocrit percentage by 10 and then dividing the resulting number by the number of red blood cells.

The normal value is from 70 to 110 (depending on age). MCV is measured in femtoliters.

Indicators below 80 are regarded as a criterion for developed anemia (although, as already mentioned, when testing the child’s blood, its level can be reduced to 70). An increase in the average volume of more than 110 can be regarded as macrocytosis.

Changes in erythrocyte volume are observed during development various diseases. For their timely diagnosis it is necessary to conduct a detailed blood test with determination of quantitative and quality characteristics shaped elements. If at least one of them is changed, then there is a hidden pathology.

Indications for blood tests

The most common indications for determining the average volume of red blood cells are:

Suspicion of anemia (decreased red blood cell count or decreased hemoglobin amount);
Family history of blood diseases. In this case, the examination must be carried out in children starting from 2 months of age.

With the exception of these indications, an extended blood test and MCV determination are performed for patients in intensive care units, surgery (at the stage of preparation for surgery), undergoing radiation or chemotherapy, as well as for patients who have been in epidemic-prone areas for some time. infectious diseases blood.

Most often, patients suffering from certain diseases have elevated MCV levels. Its decrease is somewhat less common. Below we describe in more detail those conditions in which red cell volume is increased, and those due to which it may be reduced.

Increase in mean red blood cell volume

When is the average red blood cell volume elevated? Most often, the indicator is increased with the development of hyperchromic anemia, accompanied by an increase in red blood cell size.

The main situations in which an increase in MCV is observed:

All of these conditions directly or indirectly contribute to an increase in the average volume of red blood cells, which can be detected in an extended blood test.

Reasons for decreased average red blood cell volume

Contrary to the above, MCV levels may decrease. Low level characteristic of the development of microcytic, when small, underdeveloped blood cells are present in the blood, in which the CP (color index) is reduced.

The reasons for the development of this condition and a decrease in the normal volume of red blood cells can be caused by:

Metabolic disorders (in particular, disorders water-salt metabolism). In this situation, the average volume of red blood cells is reduced due to changes in the ionic balance of cells and the release of intracellular fluid. An indicator below normal is also detected with the development of massive burns.
Hemoglobinopathies are diseases associated with impaired formation or breakdown of the hemoglobin molecule. Refers to the number hereditary diseases. As they develop, there is a disruption in functioning internal organs due to their hypoplasia (due to lack of oxygen). In addition to a decrease in MCV, they are also characterized by a decrease in the norm of the color index (which in healthy body close to 1).
Disturbances in the synthesis of red blood cells and changes in their quality indicators (for example, with sickle cell anemia). In this situation, the decrease in MCV is due to a small “framework” - the production of reduced and deformed red blood cells.

Red blood cell distribution index (RDW) is very important factor during a general blood test. This indicator shows the size and shape of red blood cells.

Red blood cells perform the transport function, thereby assisting in the penetration of oxygen into all tissues and organs and at the same time taking away toxins and carbon dioxide accumulated in the cells. IN in good condition Red blood cells are approximately the same size, which allows them to quickly stick together, forming blood clots.

How is it calculated?

The RDW indicator is calculated in percentage, the norm of which is considered to be a limit from 11.5 to 14.8. The red blood cell distribution index is determined using a mathematical equation that represents the ratio of modified red blood cells to their total mass.

Nowadays, laboratories use computer technologies that make it possible to calculate the percentage of deviation from established norm. The calculation results are presented in the form of a histogram depicting a curve that indicates probable changes in the dimensions of red blood cells.

Normal indicators

The norms of the erythrocyte distribution index depend on gender, age and the presence of certain conditions that occur in the human body. For children under one year of age, the normal rate is 11.5-18.7%. At one year of age and older, the values tend to the generally accepted norm of 11.5-14.5%.

For the female half of humanity upper limit shifts to 15.5% because they change too often hormonal background: during pregnancy, lactation, taking oral contraceptives, menopause.

For analysis, blood is taken on an empty stomach in the morning (before 9 am). It is very important that before this procedure the person does not take any medications and is in a balanced internal state.

Raising RDW

The RDW level can be elevated in some situations. The most common cause of this pathology is iron deficiency anemia. The indicator can change at different stages of pathology development, which is clearly reflected in the histogram of red blood cells:

The initial stage of anemia development is characterized by normal indices, but hemoglobin will be greatly reduced. This is the result of healthy functioning of the spinal cord.
The next stage of development in the histogram will show increase in RDW. When there are problems with hemoglobin, indicators such as the average concentration and content of hemoglobin in a blood cell and the average volume of red cells decrease.

When treating IDA, it is necessary to normalize the level of concentration of iron-containing protein and its characteristics in the human blood.

What do the reduced numbers mean?

Patients often ask what it means: “red blood cell distribution index is reduced.” Since the erythrocyte distribution index cannot be assessed without a volume indicator, it is necessary to familiarize yourself with all the options for underestimated indicators and their relationship:

RDW is low and MCV is below average - indicating problems with the spleen and liver.
RDW is lower and MCV is higher normal level- indicates availability oncological pathologies, mainly about the development of metastases in the bone marrow.

That the distribution index red blood cells RDW sd downgraded, from biological point vision cannot, in principle, be observed. For this reason, most often the patient is offered to donate blood again, observing the following conditions:

stop smoking and drinking alcohol for 24 hours before blood sampling;
do not take any medications before the analysis;
Avoid eating smoked and salty foods the day before.

In the case when the erythrocyte distribution index RDW sd is indeed reduced, which is necessarily confirmed by deviations from the norm in the MCV indicator, then this indicates the occurrence of certain pathologies. These include:

Hypochromic microcytic anemia - sometimes also called anemia. A condition in which irregularly shaped red blood cells die because they have no biological value in organism.
Malignant tumors - usually in this case we are talking about mastopathy, bone marrow and lung cancer.
Hemolysis of red blood cells is a process during which red blood cells They die without achieving their goal. As a result, active hemoglobin is released.

Causes

So, the erythrocyte distribution index is reduced - what does this mean? There are several reasons that can reduce the RDW indicator:

Acute blood loss due to injuries and pathological bleeding.
Frequent operations.
A metabolic disorder during which the food consumed is not completely digested.
Hormonal imbalance, which most often occurs in women.
Deficiency of B vitamins and iron in the body.
Blood diseases characterized by rapid destructive processes.

What measures to take?

What to do when the red blood cell distribution index is low?

A highly qualified doctor during a consultation will most likely ask the patient to take the test again, because the RDW indicator is almost never underestimated. Because this suggests that all cells are ideal in their parameters, but this cannot happen in principle. If the indicator is confirmed during repeated analysis, then a full examination of the body’s condition is carried out, paying attention to Special attention oncological examinations.

Preventive measures

Prevent reduced rate RDW is possible subject to the following simple rules:

The diet should be balanced, which includes plenty of fresh fruits, lean meats and vegetables.
It is recommended to breathe fresh air as often as possible.
An active lifestyle will help prevent a decrease in the RDW index.
It is very important not to skip routine medical examinations, during which most often serious deviations from the norm are detected that do not have external symptoms.

As a result, we learned that the red blood cell distribution index reflects their dimensions relative to each other and makes it possible to learn about their biological value. Demotion RDW indicator It is very rare, but if the erythrocyte distribution index is reduced, this means that various pathologies may be present.

The index is calculated based on the results of a general blood test, but can only be fully valid in conjunction with the MCV indicator, since they are closely interrelated.

Not always indicators of the content of erythrocytes and hemoglobin can provide answers to the questions posed. In such cases, determining MCV, RDW and some other indicators, which we will talk about, will help when making a diagnosis.

MCV – mean erythrocyte volume, or mean corpuscular volume (Mean Corpuscular Volume). Indicator characterizing average value cells (in volumetric terms). The unit of MCV is femtoliter (fl) or cubic micrometer (µm3).

Determined by a hematology analyzer by dividing the cellular volume by the number of blood cells. You should be aware that in some situations it may be unreliable. For example, if there is irregular shapes erythrocytes in patients with sickle cell anemia.

On the right in the image is a modified red blood cell in the shape of a sickle

What is the norm and what is considered a deviation

A normal value is considered when the MCV is between 80 and 100 femtoliters. The red blood cell in this case is a normocyte.

If the average volume of a red cell is less than 80 fl, it is a microcyte. Well, if the volume is more than 100, then such an erythrocyte is called a macrocyte.

Accordingly, microcytosis is distinguished when it is determined a large number of microcytes in the blood. Low hemoglobin is characteristic. Macrocytosis is characterized increased content macrocytes in the analysis.

Anisocytosis is the presence of red blood cells of different sizes and shapes.

In newborns and children under one year old, the norm is 70-110 femtoliters. With age, this indicator is compared with that of adults

When is MCV prescribed and why is it needed?

This analysis has two main goals:

Differential diagnosis of anemia.
Determination of water and electrolyte imbalances.

The determination of the MCV indicator is included in general analysis blood, does not require special preparation. It is advisable to donate blood on an empty stomach. Capillary blood is used (analysis is taken from a finger).

Prescribed to patients with anemia, metabolic disorders and severe concomitant pathologies.

By this analysis it is possible to identify the type of water-electrolyte imbalance. Thus, with macrocytosis, hypertonic overhydration is likely, and with microcytosis, hypotonic dehydration is possible. It goes without saying that this is just helper method, giving us one of the signs of a particular violation.

Causes of Low MCV

The average volume of red cells is reduced when:

dehydration and development of hypertensive dehydration;
microcytic and with a lack of hemoglobin;
hereditary, genetically determined blood diseases, for example, thalassemia;
lead poisoning;
hemoglobinopathies and impaired synthesis of porphins (component of hemoglobin).

Causes of elevated MCV

The average volume of red cells is increased when:

liver diseases;
development of water-electrolyte imbalance in the form of hypotonic overhydration, which is possible with kidney diseases;
macrocytic and megaloblastic anemia;
deficiency of folic acid and vitamin B 12;
myelodysplastic syndrome.

Anemia cannot be ruled out when MCV is not higher than normal. For example:

after bleeding;
with hemolytic anemia;
for some acute poisonings.

A little about anisocytosis

Anisocytosis is the presence of red blood cells in the blood. different sizes– from microcytes to macrocytes. Quantitatively, the distribution of red blood cells by volume is expressed in a special index, designated RDW.

This is what the distribution width of erythrocytes by volume curve looks like in the analysis

Red blood cell heterogeneity by volume (RDW) shows the deviation from the standard volume, expressed as a percentage.

Anisocytosis can be determined by a blood smear under a microscope, but the exact characteristics of these indicators are obtained using hematological analyzers. The results are interpreted by doctors laboratory diagnostics together with MCV and facilitates the diagnosis of anemia.

Normally, the width of the distribution of red blood cells is 11.5-14 percent.
You should know that if MCV is reduced with normal RDW, then this is typical for blood transfusion, removed spleen, and thalassemia.

If MCV is elevated with RDW standard, then most likely there is liver pathology.
If RDW is elevated and MCV is below normal, beta thalassemia, iron deficiency, or red blood cell sludge may be suspected.

If suddenly both indicators are higher than normal, then we can assume cold agglutination, vitamin B 12 deficiency or a violation of its absorption. This combination is also typical after a course of chemotherapy for cancer.

Increased heterogeneity of red blood cells

Heterogeneity is increased when:

iron deficiency anemia;
liver diseases;
myelodysplastic syndrome and tumor metastases to the bone marrow.

In any case, deciphering these indicators and making a diagnosis based on them is the sole task of the doctor. The results of an advanced blood test, including indicators such as erythrocyte heterogeneity by volume and average erythrocyte volume, will greatly facilitate clinical analysis anemia.