Not always, when making a diagnosis associated with diseases of the circulatory system, it is sufficient to determine the quantitative content of erythrocytes (red blood cells) and hemoglobin in the blood.
To obtain a detailed picture of the composition of the blood, the average volume of erythrocytes is measured - a more important and detailed hemolytic analyzer that characterizes the formed elements not from the quantitative, but from the qualitative side.
It is established by the ratio of the total volume of erythrocytes contained in a portion of blood to their number.
The result allows you to determine the average volume of one erythrocyte, which may be normal, and may be significantly lower or higher than the norm.
Any deviation allows, in combination with other erythrocyte indices, to suggest its reasons leading to this, and to correctly diagnose.
This analysis is usually denoted by the abbreviation MCV, which translated into Russian means the mean (Mean) corpuscular (Corpuscular) volume (Volume).
The units of measurement accepted in most laboratories are femtoliter (fl) or cubic micrometer (μm 3). It should be borne in mind that for some diseases, this analysis is not reliable.
Limits of the norm by age category
The indicator is called the norm if the values of the average volume of erythrocytes are in the range of not less than 80 and not more than 100 femtoliters. In newborns, the range of the norm is somewhat wider - from 70 to 110. With age, a person tends to increase the indicator, from the minimum of the norm to the maximum, which is a physiological norm and does not require medical intervention.
MCV values are gender independent.
There are several erythrocyte characteristics in total:
The state of the blood will be called under such conditions normocytosis, microcytosis, macrocytosis, or anisocytosis.
Macrocytosis, microcytosis and anisocytosis are accompanied by a certain pathology of the circulatory system, or a tendency to it. For example, the detection of a large number of microcytes indicates a lack of hemoglobin in the blood. Macrocytosis may indicate liver problems or hormonal imbalances.
| Age | Allowable values, or norm, fl |
|---|---|
| 1 - 3 days | 75 – 121 |
| 7 days | 86 – 126 |
| 14 - 30 days | 88 – 124 |
| 2 months | 77 – 115 |
| 3 - 6 months | 77 – 108 |
| 16 years | 73 – 85 |
| 7 - 10 years old | 75 – 87 |
| 10 - 15 years old | 76 – 95 |
| 16 - 20 years old | 78 – 98 |
| 21 - 40 years old | 80 – 98 |
| 41 - 65 years old | 80 – 100 |
| over 65 years old | 78 – 103 |
When is MCV Analysis Needed?
The doctor directs to determine the average volume of red blood cells for the following purposes:
- To give a deeper assessment of the developing anemia;
- Identify metabolic disorders;
- Determine the degree of violation of the water-electrolyte balance in the patient;
- To adjust the treatment of severe pathologies.
This analysis is only an auxiliary method that sheds light on the nature of disorders in the body.
The reliability of this method in identifying various types of anemias or violations of water and electrolyte balance is beyond doubt.
So, hypertensive hyperhydration in most cases is accompanied by macrocytosis, and in hypotensive patients, indicators of microcytosis are recorded.
The MCV indicator, along with other 20 indicators, is included in the general analysis, for which capillary blood is taken from a finger. To prevent measurement errors, it is recommended not to eat before analysis.
For what blood diseases can the analysis be within the normal range?
Often, with severe anemias associated with a deficiency in the formation of hemoglobin, the volume of erythrocytes may remain within the normal range.
This is observed in the following situations:
When the average volume is lowered: what does it mean?
If the MCV is below normal in the blood test, then this indicates one of two situations:
- Erythrocytes, the main function of which is the transportation of hemoglobin through the tissues of the body, contain an insufficient amount of it;
- For some reason, there is an intense destruction of already matured erythrocytes.
These conditions, in which a low MCV, are characteristic when:
If a child's blood count is lowered to 75 fl, then he is diagnosed with microcytic anemia.
When the average volume of red blood cells is increased
An increase of 115 feet is typical for the following situations:
RBC maturation What does anisocytosis say?
If erythrocytes of different sizes are found in the blood - both micro- and macrocytes, then for their characteristics the distribution by volume of red blood cells is determined, which is denoted by the abbreviation RDW.
It is measured using a hemolytic analyzer that differentiates the middle cells and determines the heterogeneity of erythrocytes, that is, the deviation from the standard volume, and is expressed as a percentage.
The RDW rate is 11.5-14%. For the correct differentiation of anemias and other pathologies, the RDW measurement is always carried out in conjunction with the MCV measurement.
With these measurements, the following patterns were revealed:
- Decreased MCV with normal RDW indicates blood transfusion, thalassemia, and removed spleen.
- With elevated MCV and normal RDW, liver pathologies are observed.
- If MCV is low and RDW is elevated, iron deficiency, beta thalassemia, or erythrocyte sludge syndrome is suspected.
- If both indicators are elevated, then vitamin B12 deficiency, the effects of chemotherapy, or cold agglutination are assumed.
It is characteristic that in all the presented violations of blood structures, one of the most significant reasons is the deficiency of vitamin B12 in the body, and this is not accidental.
This vitamin is the most important factor in hematopoiesis, since only in its presence bone marrow stem cells can differentiate towards oxygen carriers, that is, erythrocytes.
And even if all the other necessary elements of erythrocyte synthesis are present, with a lack of B12, the hematopoietic chain will break.
This main vitamin for blood comes to us both from the outside, with food, and is synthesized in large quantities in the large intestine through the vital activity of beneficial microflora (bifidobacteria and lactobacilli).
Therefore, in order to prevent violations of the hematopoietic function, not allowing a reduced amount of this element in food, monitoring the health of the intestines and rational nutrition is a paramount task.
One should not trust the MCV indicator alone without supporting it with the indicators of other erythrocyte indices. For example, the average volume of red blood cells will not be accurate if abnormal bodies are found in the blood.
Only an integrated approach to assessing blood parameters will allow the doctor to identify the incipient pathology in a timely and qualified manner and determine the diagnosis as accurately as possible.
Video: Red blood cells. Volume.
A general blood test determines a number of its characteristics that allow a specialist to assess the patient's health. One of its key indicators is MCV in the study of blood. 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 red blood cells (erythrocyte index), which allows you to determine the state of these blood cells in a person. Erythrocytes are blood cells that give the blood a 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. Red blood cells play a very important role in all processes that occur in the human body. Changes in these characteristics indicate the development of allergic reactions, inflammatory processes, deficiency of vitamins and microelements.
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, the patient may be subjected to a separate study to identify this characteristic.
The average red blood cell volume can be calculated by dividing the sum of cell volumes by the total number of red blood cells in the blood. The MCV unit is femtoliters (fl, fl) or microns 3. This blood indicator is used to diagnose various types of anemias (low levels of hemoglobin in the blood), since each type of this disease requires the appointment of a certain therapy.
Normally, the values of the average volume of red blood cells will depend on the age of the person.
Consider the values of the MCV norm in the blood test, in fl:
- children under 14 days of age - 88–140;
- children under 1 month old - 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 years old - 75–93;
- children under 15 years old - 76–95;
- boys under 18 years old - 75–94;
- girls under 18 years old - 77–98;
- men under the age of 45 - 82–98;
- women under 45 years old - 83–100;
- patients under 65 years old - 80-102;
- men over 65 - 82-103;
- women after 65 years - 80-102.
Deviations from the MCV norm in the patient's blood test give the doctor reason to diagnose the presence of such forms of anemia as microcytic, normocytic or macrocytic anemia.
A decrease in MCV in a blood test indicates the development of microcytic anemias, which can be caused by:
- iron deficiency 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 the blood test for MCV, a high level of this indicator accompanies macrocytic types of anemias and other pathologies, in particular:
- megaloblastic anemia resulting from protein deficiency;
- malignant hereditary anemia;
- failure of the pancreas;
- bowel disease;
- toxic or drug poisoning;
- impaired absorption of vitamin B12;
- hypothyroidism;
- liver disease.
As for normocytic anemias, 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 erythrocytes makes it possible to assess the development of violations of the water-electrolyte balance in the patient's body. A decrease in MCV in the blood test is a sign of the hypertensive nature of these disorders, and its high rates are associated with their hypotonic nature.
When taking a general blood test, many indicators are taken into account. It is with the help of these indicators that the doctor analyzes the patient's condition and prescribes treatment. Among such indicators may be MCV. What is MCV in a blood test?
MCV in the analysis (without ESR) shows the number of erythrocytes. It is also called the general erythrocyte index. Is this indicator important? Of course, since it is with the help of it that the general condition of red blood cells in the blood can be assessed. Red blood cells are red blood cells. It is thanks to them that the blood becomes red. Their number significantly exceeds the content of other elements in the blood. The shape of the blood cells resembles a flat disc concave on both sides. Taurus do not have a nucleus.
So, the main functions of red blood cells:
- Thanks to these little bodies, the blood takes on its red color.
- Contains hemoglobin, which transports air to all human organs.
- Maintain water-salt balance.
- Red blood cells also help maintain the temperature in the human body.
- Provide some immune functions in the body.
Red blood cells play a rather important role in the human body. That is why it is so important to monitor their number, periodically take a general blood test. The slightest changes in the content of red blood cells may indicate the onset of an inflammatory process or an allergic reaction.
To determine the number of red blood cells, a general (clinical) analysis is taken.
However, in some cases, patients are prescribed a special MCV blood test, which is aimed at determining the number of red blood cells. The meaning and interpretation of the MCV blood test is done by the attending physician. It is highly discouraged to do it yourself.
Analysis decoding
How to determine MCV in a blood test? To determine the number of red blood cells, the patient takes a clinical blood test. Blood cells have a constant composition, which is why, if their content has changed dramatically, the patient's condition deteriorates markedly.
How is the average red blood cell count determined? This indicator is calculated using a special formula:
MCV = ((%) hematocrit * 10): erythrocyte count 106 μl
It is by this formula that the MCV is calculated in the blood test. What is the normal content of this indicator in the blood? The content of red blood cells depends on the age of the patient. Thus, we can say that the rate of MCV in the blood is different for everyone. Indicators vary especially strongly in children.
The average volume of red blood cells is the norm in a child:
- less than 12 months - 71-112fl;
- from 1 to 5 years old - 73-86 fl;
- from 5 to 10 years old - 75-87 fl;
- from 10 to 12 years old - 76-94 fl;
- from 12 to 15 years old - 74-95 fl.
Among women:
- from 15 to 18 years old - 78-98 fl;
- from 18 to 45 years old - 81-100 fl;
- from 45 to 65 years old - 81-101 fl;
- over 65 years old - 81-102 fl.
In men:
- from 15 to 18 years old - 79-98 fl;
- from 15 to 18 years old - 80-99 fl;
- from 45 to 65 years old - 81-101 fl;
- over 65 years - 81-103 fl.
It is these MCV indicators that are considered normal. Any deviations from the norm may indicate the onset of an inflammatory or infectious process in the body.
Decreased performance
What does the reduced average volume of red blood cells in the blood say? If the MCV in the blood test decreases to 75 fl, then this may indicate the presence of anemia in the patient. However, you should not be afraid in advance. MCV decoding is the responsibility of the attending physician. The reasons for low MCV can be varied.
MCV lowered - reasons:
- Changes in the water-salt balance in the body.
- Hypertensive dehydration (high level of fluid deficiency). May occur with insufficient use of water and other liquids.
- MCVs in the blood test are lowered with the onset of anemia. Anemia is anemia.
- A disease in which the synthesis of hemoglobin in the body is disrupted.
- Low iron content in the body.
- The use of certain medications.
The most common decrease in MCV is due to anemia. Leukemia can occur for many reasons. Among them: problems with the gastrointestinal tract, chronic diseases in which blood loss is observed, pregnancy, the action of various infections, a lack of iron in the body. If the average volume of erythrocytes is low, then a consultation with your doctor is necessary.
Anti-MCV shows the amount of antibodies. Anti-MCV can be determined using biochemical analysis. Detecting antibodies will help prevent the development of rheumatoid arthritis. These elements can appear several years before the disease begins to develop.
If the level of the average number of red blood cells is below normal in children, this may indicate the development of anemia. Children are especially sensitive to this disease.
Symptoms of anemia in children:
- Lethargy.
- Decreased activity.
- Refusal to play and communicate.
- Dyspnea.
- Frequent gagging.
- Puffiness.
- Body weight does not change for a long time.
Increased values
What does an increased volume of red blood cells mean? The average volume of red blood cells is increased in the event that the patient has a lack of vitamin B. Most often it is B12.
MCV elevated - reasons:
- The use of tobacco products.
- Taking hormonal contraceptives.
- Alcohol abuse.
- With diseases of the endocrine system - myxedema.
- Liver disease.
- Diseases of the organ that reproduces blood - bone marrow.
- Taking antidepressants.
- Anemia.
- Disorders in the work of the pancreas.
- Intoxication of the body.
It is for these reasons that the level of red blood cells rises. Thanks to the delivery of an analysis for MCV, it is possible to identify the development of alcoholism at an early stage. To control the level of MCV, you should periodically take a clinical analysis. Diseases detected at an early stage are much easier to cure than neglected ones.
So, MCV is the average volume of red blood cells. It can be either decreased or increased. Normal indicatorsMCVdepend on the patient's age... Red blood cells decrease due to the development of anemia, the use of certain drugs, changes in the balance of water in the body. Increased indicators of the average volume of red blood cells occur due to the use of alcohol and tobacco products. An increase in MCV levels quite often occurs in women when taking hormonal contraceptives. To monitor MC, a complete blood count should be taken.
It allows you to determine the quantitative and qualitative composition, which in turn indicates the state of human health and the presence of any problems. In addition to leukocytes and platelets, erythrocytes are carefully examined. These red blood cells carry out a transport function, delivering nutrients and oxygen to all cells and organs. One of the indicators of their level is the erythrocyte index, designated MCV. This index allows you to estimate the number and size of red blood cells, which in turn is associated with the general state of the body. What else does MCV say in a blood test, what it is and what norm indicators are set, we will find out further.
The erythrocyte index MCV shows the total volume of red blood cells in the blood. In a healthy person, this coefficient is a constant value, a change in which entails pathological changes in the body.
Allocate two main indicators that determine the need for analysis:
- Determination of violations of the water-salt balance (with intestinal infections, acute respiratory infections and acute respiratory viral infections).
- Diagnosis of anemia (iron deficiency).
Also indications for research can be manifestations such as:
- hormonal disruptions;
- metabolic disease;
- obesity;
- diabetes;
- low immunity.
Most often, MCV analysis allows you to identify various forms of anemia:
- normochromic anemia - develops with bone marrow pathologies that are caused by the presence of chronic diseases;
- macrocytic anemia - a pathological increase in red blood cells in size due to a lack of B vitamins and folic acid;
- microcytic anemia - develops as a result of acute iron deficiency, as a result of which the synthesis of polypeptide chains decreases.
A healthy person normally has an MCV of 80 to 100 femtoliters. This indicator is a nomrocyte, which means full compliance with the established norm. An excess of more than 100 femtoliters is a macrocyte, and a decrease of less than 80 is a microcyte.
Measurement units and calculation
The average volume of an erythrocyte is measured in femtoliters or cubic micrometers. This erythrocyte index is determined using a mathematical formula that displays the ratio of hematocrit as a percentage of the total number of erythrocytes, after which the resulting value is multiplied by 1012 liters.
How is the analysis done?
In medical practice, MCV can be included both in a general blood test, and it can be performed without taking into account the rest of the blood fractions. For analysis, you will need blood from a finger or vein, taken in accordance with all the rules:
- the patient does not eat or drink 3-5 hours before blood sampling;
- women do not have menstruation;
- the person feels well (no coma and cardiac shock).
A smear is prepared from the resulting blood, which is further examined under a microscope, highlighting the necessary indicators. Further, the indicators are entered into the formula, obtaining the desired value.
Decoding the results
After the analysis has been carried out, the patient is given a sheet that contains numerical indicators. The decryption can be contained both in the analysis sheet itself, and it can be performed orally by the attending physician.
Indicators of the norm related to the person's age:
- newborns - 100-140 fl;
- the first year of life - 75-110 fl;
- 2-5 years old - 75-95 fl.
- 5-10 years old - 70-85 fl;
- 10-18 years old - 80-95 fl.
Usually, the decryption is presented in the form of a table, which indicates the name of the research parameter, its numerical indicator, norm, degree of deviation. This allows us to compare the clinical manifestations of diseases with their course at the micro level. The average volume of red blood cells is of great clinical importance, since it is interconnected with other blood parameters.
Increased values
If the analysis showed that the average volume of red blood cells is higher than normal, this indicates the development of such a pathological condition as macrocytic anemia.
She may accompany the course of the following diseases.
MCV (from the English mean corpuscular volume) is one of the erythrocyte indices, which shows the average volume of erythrocytes. This indicator is able to characterize the entire population of red blood cells in the blood. The calculated measure denotes the average volume that one erythrocyte takes. The value of this index is calculated by the formula: hematocrit as a percentage, multiplied by 10 and divided by the total number of red blood cells in the blood. In most laboratories, MCV is measured in cubic microns (μm2) or femtoliters (fl).
A change in the erythrocyte composition of the blood is one of the main laboratory criteria in the diagnosis of anemia, therefore, the calculation of the average volume of erythrocytes in combination with other indicators of the clinical blood test is used for differential diagnosis, monitoring and evaluation of the effectiveness of treatment of anemia and diseases of the hematopoietic system, determination of violations of the water-electrolyte balance.
MCV in a blood test is calculated automatically - using a hematology analyzer, which determines the average volume of all measured red blood cells.
Red blood cells and their function in the body
Red blood cells are red blood cells that contain hemoglobin. Their main function is to transport oxygen and carbon monoxide between the lungs and tissues of other organs. In addition, erythrocytes are involved in the reactions of the immune system, play a significant role in maintaining the acid-base balance, serve as a means of transporting nutrients (glucose, amino acids, salts, fatty acids) and decay products (uric acid, urea, ammonia, creatine).
Red blood cells form in the bone marrow. Their life cycle is 120 days, after which the erythrocytes are metabolized by the cells of the liver, spleen and bone marrow. They are being replaced by young forms of red blood cells called reticulocytes. Before entering the microvasculature, cells go through several stages of development, during which their shape, size and chemical composition change. For the normal synthesis of red blood cells, a sufficient supply of vitamin B12, iron and folic acid is necessary.
Mature erythrocytes are nuclear-free cells in the form of biconcave discs, which allows them to penetrate into the narrowest and most curved areas of the vascular bed. Due to the plasticity of erythrocytes, the viscosity of blood in small capillaries is much lower than in large ones.
The average diameter of a red blood cell in an adult is between 6.8 and 7.5 microns. Red blood cells with a diameter of less than 6.8 microns are called microcytes, and a condition in which the size of peripheral blood red blood cells is much less than normal means the presence of microcytosis. The presence in the blood of abnormally large erythrocytes (macrocytes) with a diameter of more than 8 microns makes it possible to suspect macrocytosis in the patient.
The determination of the erythrocyte index is performed as part of a general blood test, but it can also be prescribed as a separate study.
The indicator of the average volume of erythrocytes has diagnostic value in assessing micro- and macrocytosis, it is used in calculating the average content and concentration of hemoglobin in erythrocytes.
Normal MCV Values
The norm of MCV in the blood test varies depending on age: in newborns it is maximum, in children in the first days and months of life, its range is somewhat wider than in adults, after a year the indicator decreases, and by the age of 18 it is fixed at a level of 80 to 100 fl. This means that with age, the level of the average volume of red blood cells becomes lower. For men and women, the MCV rate and the interpretation of the blood test will also be different. In addition, the norms of blood parameters may differ depending on the method of determination, laboratory, units of measurement.
Normal MCV values by gender and age
|
Girls - up to 128 fl Boys - up to 128 fl |
|
|
Girls - up to 100 fl Boys - up to 100 fl |
|
|
1 week to 1 year |
Girls - 77-79 fl Boys - 77-79 fl |
|
Girls - 72-89 fl Boys - 70-90 fl |
|
|
Girls - 76-90 fl Boys - 76-89 fl |
|
|
Girls - 76-91 fl Boys - 76-81 fl |
|
|
Girls - 79-93 fl Boys - 79-92 fl |
|
|
Women - 82-96 fl Men - 81-93 fl |
|
|
Women - 91-98 fl Men - 80-93 fl |
|
|
Women - 80-100 fl Men 81-94 fl |
|
|
Women - 82-99 fl Men - 82-94 fl |
|
|
Women 80-100 fl Men - 81-100 fl |
|
|
65 and older |
Women - 80-99 fl Men - 78-103 fl |
An increase or decrease in the MCV index in the general blood test may indicate various diseases and pathological conditions, for example, a violation of the water-salt balance: with a decrease in the average volume of erythrocytes, the disorders are hypertensive, and with an increase, they are hypotonic.
The average red blood cell count often decreases during pregnancy in women who are iron deficient.
Reasons for increasing MCV
An increase in MCV in the blood may indicate a lack of vitamin B12, a lack of folic acid, the development of hyperchromic or macrocytic anemia, myelodysplastic syndrome, pathologies of the liver, bone marrow, renal failure, myxedema, hypothyroidism. The indicator of the average volume of erythrocytes can be increased in case of methanol poisoning, alcohol abuse, smoking, and taking certain medications.
A false overestimation of the average volume of erythrocytes can occur with hyperglycemia and diabetic ketoacidosis, cold agglutination of erythrocytes.
MCV in the blood test is lowered
The MCV index can be lowered in the case of microcytic anemia (iron deficiency, sideroblastic), hypochromic anemia with a lack of hemoglobin, thalassemia, with renal diseases that increase the level of erythropoietin, hypertensive dehydration, blood loss, conditions accompanied by impaired formation or increased destruction of the liver with tissue changes, erythremia, hypothyroidism, cancer and autoimmune diseases. The average red blood cell count often decreases during pregnancy in women who are iron deficient. The reason for the decreased rate may be lead poisoning, mechanical hemolysis, the presence of giant platelets.
To confirm or refute the diagnosis, additional studies are prescribed: a biochemical blood test, determining the level of hormones, identifying tumor markers, immunological tests, ultrasound and others.
How is MCV blood test done?
The determination of the erythrocyte index is performed as part of a general blood test, but it can also be prescribed as a separate study.
The value of the MCV index is calculated using the formula: hematocrit as a percentage, multiplied by 10 and divided by the total number of red blood cells in the blood.
Blood sampling is performed on an empty stomach, after an overnight fasting period of at least eight, and preferably ten to twelve hours. On the eve of the analysis, it is recommended to refrain from excessive physical and psycho-emotional stress, to exclude physiotherapy procedures.
MCV in a blood test is calculated automatically - using a hematology analyzer, which determines the average volume of all measured red blood cells. The manual calculation method, in which the laboratory assistant himself counts the cells and makes calculations according to the formula, is rarely used.
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