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The average volume of erythrocyte
Last reviewed: 20.11.2021
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The average volume of erythrocyte - MCV (mean corpuscular volume) is measured in femtolitra (fl) or cubic micrometers. In hematological analyzers MCV is calculated by dividing the sum of cellular volumes by the number of red blood cells. This parameter can also be calculated using the formula: Ht (%) × 10 / RBC (10 12 / l).
The values of MCV, which are within 80-100 fl, characterize the erythrocyte as a normocyte, less than 80 fl - as a microcite, more than 100 fl - as a macrocite. MCV can not be reliably determined if there are a large number of abnormal red blood cells (for example, sickle cells) or a dimorphic erythrocyte population in the blood.
The average volume of red blood cells is one of several erythrocyte indices, which allows you to accurately estimate the number and size of the red cells that are so important for the health in general and for the blood. The most significant and numerous, these blood corpuscles perform a variety of functions, including:
- Transportation of oxygen and carbon dioxide, that is - respiratory function;
- Transportation of adsorbed amino acids and lipids to tissues, that is - nutritional;
- Transport of enzymes;
- Regulation of acid-base balance, carried out by hemoglobin;
- Adsorption of microbial toxins, antibodies;
- Active participation in fibrinolysis and in the work of hemostasis in general.
The average volume of erythrocyte is part of a general hematological, clinical study of blood. This index is denoted by the acronym MCV - Mean Corpuscular Volume, which translates as corpuscular (from the word "corpuscle" - a very small particle) averaged volume. Such an indicator helps to reliably determine the amount and volume of red blood cells in the blood stream, and also to objectively estimate their size. However, the average volume of erythrocyte sometimes can not be an absolutely reliable informative source, as happens with some deviations in the composition and blood formula. For example, anisocytosis (change in the size of red bodies) or poikilocytosis (red blood cells of different shapes) does not allow accurate determination of MCV.
What is the average volume of the erythrocyte?
This information is necessary for the doctor, because according to the average size of the erythrocyte, he can specify the type of hematological problem - anemia, if it is supposed to be based on clinical symptoms. For example, if there is an acute shortage of iron in the body, then most likely MCV will confirm a microcetary haematological problem. If a person suffers from a deficiency of cyanocobolamine, that is, vitamin B12, then the average volume index argues for the presence of macro-anemia. In addition to differentiation of anemia, the average volume of the erythrocyte clearly shows the ratio of the water-electrolyte balance, especially in the intravascular and intracellular sectors. If MCV is significantly higher than the normal age range, this means the presence of hypotonic disorders, with a decrease in the norm, one can speak of hypertonic dehydration (dehydration).
What is the procedure for taking blood to determine the average volume of red blood cells?
MCV are additional, concretizing information in the general picture of the clinical examination, these tests are not separately assigned separately. In general, the hematological section is important and necessary for the evaluation of blood indicators, and the procedure for its conduct is likely to be familiar to many. Depending on the expected diagnosis and the number of indicators needed by the doctor, blood as a laboratory material for complex research is taken from the vein, but sometimes only capillary blood is needed. There are no special requirements to the patient, except that the test is given on an empty stomach and is carried out in the morning.
How is the average volume of red blood cells calculated?
The unit of measure MCV is a femtoliter, which, strangely enough, was previously a Dutch measure of alcohol-containing liquids. Often the mean erythrocyte volume is measured in micrometers as well. The study of the average volume is carried out in conjunction with the calculation of all the red cells in the pulses that occur when the cells pass through the microscopic apertures of the hemolytic analyzer. As a result, a histogram is obtained showing how the red blood cells are distributed according to the total volume.
What is the norm of such an indicator as the average volume of the erythrocyte?
The average volume of erythrocyte according to established standards ranges from 80 to 100 femtoliters. Thus, if the indicator fits within the indicated boundaries, the erythrocyte is designated as a normocyte. If below 80 femtoliters, the erythrocyte is characterized as a microcite, above - a macrocycle. It should be borne in mind that the average volume of erythrocyte in a person can vary throughout life, but there are limits to the norm. Thus, in newborn infants, this indicator begins with 128 femtoliters, and then decreases to 100. Already at one-year-old age, the MCV can have about 77 fl., And by the age of five it is leveled to the norm-80 fl. Most often, the average volume of erythrocyte as a refinement of the type and stage of anemia is studied in conjunction with the color index and MCH - an indicator of the quantitative content of hemoglobin in the erythrocyte. This is a rather specific calculation, so do not go into the independent study of the laboratory form, it is better if this necessary and important information falls into the hands of a professional, that is, a doctor.