The norm of erythrocytes in children and the reasons for its increase

The norm of erythrocytes in children and the reasons for its increase

25.05.2022 0 By admin

The total blood count in a child includes an indicator of the number of red blood cells. The normal rate is different at different ages and also varies depending on gender: from 3.8 to 5.6 * 10 * 12 / l. Girls have fewer red blood cells than boys. For example, in girls aged 13-19, the norm is 3.5-5.0 * 10 * 12 / l, and in boys: 4.1-5.5 * 10 * 12 / l. An increase in the level of red blood cells can be with dehydration (for example, as a result of vomiting and diarrhea), renal ischemia, oxygen starvation and endocrine diseases.

Erythrocytes are biconcave red blood cells. These are nuclear-free cells, consisting of hemoglobin and a protein-lipid membrane. Erythrocytes are formed in the red bone marrow and live up to 120 days. The large surface of red blood cells makes it easy to carry gases around the body. By bringing oxygen to the tissues and taking carbon dioxide from them, red blood cells provide a transport function.

Hematopoiesis in children

In the blood of healthy newborns, relative polycythemia is noted, that is, an increased number of cellular elements. The number of erythrocytes increases in response to severe hypoxia during childbirth, and also due to the partial transition of the liquid part of the blood into the intercellular space. Already on the second day after birth, the synthesis of erythropoietin decreases and the rate of erythropoiesis decreases, since oxygenation through the lungs quickly saturates the body with oxygen. In the first week of life, extramedullary erythropoiesis is completed, and the red bone marrow becomes the main site of hematopoiesis.

increased red blood cells in a child

After the birth of a child, the content of reticulocytes in the blood decreases from 31% to 15%.


Erythropoietin is a renal hormone that stimulates hematopoiesis. The bulk of erythropoietin is produced in the kidneys. The substance activates the division and maturation of red blood cells from precursor cells, and also increases their lifespan. The normal concentration of erythropoietin in the blood serum is 10-30 mIU/ml. Oxygen starvation due to bleeding, anemia or any other reason triggers the synthesis of the hormone. Renal ischemia is a powerful stimulator of erythropoietin secretion. A certain role in increasing its content is played by glucocorticoids and some other hormones that increase oxygen consumption.

Recombinant erythropoietin-alpha is used as a drug for anemia caused by chronic renal failure.

Complete blood count in children

A complete blood count is the first step in diagnosing diseases. Children take blood from a finger. For accurate results, it must be taken in the morning on an empty stomach. A clinical blood test allows you to evaluate the quantitative and qualitative changes in the cellular composition. They can be a transient response of the body to an irritant or a manifestation of a disease. Testing for prevention in children should be carried out once a year.

Main indicators of UAC:

  • hemoglobin, HGB;
  • erythrocytes, RBC;
  • hematocrit, HTC;
  • mean volume of erythrocytes, MCV;
  • mean erythrocyte hemoglobin content, MCH;
  • mean erythrocyte hemoglobin concentration, MCHC;
  • leukocytes, WBC and certain types of leukocytes as a percentage;
  • platelets, PLT;
  • ESR.

Leukocytes in the leukocyte formula are represented by agranulocytes and granulocytes. Agranulocytes include monocytes and lymphocytic cells. And basophils, eosinophilic cells and neutrophils belong to granulocytes.

Normal RBC count in children

Each stage of life is characterized by its own norm of blood counts. The absolute number of erythrocytes varies depending on age, and after 12 years – also taking into account gender.

The norms of erythrocytes in children by age:

  • the first day of life: 4.3-7.6 * 10 * 12 / l;
  • 1 month: 3.8-5.6*10*12/l;
  • six months: 3.5-4.8 * 10 * 12 / l;
  • year: 3.6-4.9 * 10 * 12 / l;
  • 1-6 years old: 3.5-4.5*10*12/L;
  • 7-12 years old: 3.5-4.7 *10*12/L;
  • in girls 13-19 years old: 3.5-5.0 * 10 * 12 / l;
  • in boys 13-19 years old: 4.1-5.5 * 10 * 12 / l.

The rate of reticulocytes, erythrocyte precursor cells, for adolescents is 2-11%.

Why are red blood cells elevated in a child?

Erythrocytosis is an increase in the level of red blood cells above 5 * 10 * 12 / l. If the number of red cells and other blood cells increases, and the total volume of blood does not change, then hemoglobin with hematocrit also increases. Low ESR is an indirect indicator of erythrocytosis. The erythrocyte sedimentation rate decreases with increasing blood viscosity.

The increase in red blood cells can be absolute, with increased erythropoiesis, and relative, due to blood clotting as a result of plasma loss.

Increased red blood cells in children: what does it mean?

  • The relative growth of erythrocytes is observed during dehydration due to vomiting or diarrhea, as well as in conditions of redistribution of circulating blood from the vascular bed to the intercellular space during burn disease and shocks of various etiologies.
  • Secondary erythrocytosis is an increase in the number of erythrocytes per unit volume of blood in response to hypoxia. Oxygen starvation stimulates the production of erythropoietin, which, in turn, activates hematopoiesis. Hypoxia develops in diseases of the respiratory system such as bronchitis and asthma, as well as in heart defects and obstructive sleep apnea syndrome. Residents of mountainous areas constantly experience mild hypoxia, for them secondary erythrocytosis is an adaptive mechanism.
  • Polycythemia vera or Wakez’s disease is a tumor disease of the hematopoietic tissue, characterized by excessive growth of the erythroblastic germ. At the same time, there is an increased synthesis of red blood cells and an increase in the volume of circulating blood. The number of platelets and granulocytes also increases, but to a lesser extent. Wakez disease in children is extremely rare. Typical manifestations of polycythemia: skin redness, headaches, visual disturbances, high blood pressure, paresthesia. Erythromelalgia is a prominent symptom of Wakez’s disease, in which patients experience burning pain in the fingertips, which is relieved by aspirin. The diagnosis of polycythemia vera is confirmed by the detection of the JAK2 V617F genetic mutation. Cytological examination of the bone marrow in Wakez disease is characterized by hyperplasia of all myeloid blood sprouts with displacement of adipose tissue. In addition, there is a high content of hemoglobin. Endogenous erythropoietin, on the contrary, is reduced, since the pathological progenitor cell of erythrocytes is able to create new erythrocyte colonies without the help of erythropoietin.

increased red blood cells in a child

Blood with a high content of erythrocytes is characterized by a thick consistency and slow movement in the bloodstream.

  • Renal ischemia caused by pathologies such as renal artery stenosis, hydronephrosis, and polycystic kidney disease is a likely cause of erythrocytosis. With polycystic kidney tissue, multiple cavities filled with fluid are observed. Gradually, cysts increase in size and compress healthy tissue. Insufficient blood circulation causes local hypoxia, which stimulates the synthesis of erythropoietin. A similar mechanism is seen in hydronephrosis . Violation of the outflow of urine leads to a gradual expansion of the renal pelvis and calyces. Enlarged renal structures compress the supply vessels, causing local hypoxia.
  • Tumors producing erythropoietin: hypernephroid cancer, hepatoma, ovarian cancer, cerebellar hemangioblastoma.
  • Violations of the neurohumoral regulation of the kidneys – activation of the sympathetic nervous system stimulates erythropoiesis.
  • Glucocorticoids – hormones of the fascicular zone of the adrenal cortex, stimulate the synthesis of erythropoietin. Therefore, an increased content of glucocorticoids, in particular cortisol, will stimulate erythropoiesis. An increase in steroids in the blood is observed with excessive secretion of ACTH (Itsenko-Cushing’s disease), tumors of the adrenal gland (Itsenko-Cushing’s syndrome), as well as during treatment with corticosteroid drugs.
  • Endocrine diseases with high production of catecholamines, for example, in pheochromocytoma, and thyroid hormones in thyrotoxicosis, can also cause an increase in red blood cells, since these hormones increase oxygen utilization.
  • Hereditary absolute erythrocytosis develops with a genetic disorder in the structure of the globin molecule. At the same time, hemoglobin is able to attach oxygen, but is not able to give it to the tissues. Thus, hypoxia develops and the level of erythropoietin increases.

When detecting elevated red blood cells in a child, you should not immediately sound the alarm. Most often, this condition is in the nature of relative erythrocytosis. Hereditary or congenital pathology that provokes erythrocytosis is quite rare. Sometimes it is not easy to figure out why it developed. In the presence of characteristic complaints and deviations in the general blood test, it is necessary to consult a hematologist.


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