Erythrocyte parameters

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Erythrocytes (RBC, red blood cells)

Increasing the number of red blood cells (more than 6.0 1012/L in men and more than 5.0 1012/L in women) - polycythemia - can be absolute (the increase in mass of circulating red blood cells due to the enhanced erythropoiesis (formation in the bone marrow)), and relative (decrease in volume of the liquid part of blood - plasma - blood clots without increasing the mass of red blood cells and increased erythropoiesis).

Erythrocytoses (polycythaemias)

The main pathogenetic groups
Clinical forms (conditions)
Absolute erythrocytosis (polycythemia) - due to increased production of red blood cells:  
- primary polycythemia erythremia
- symptomatic erythrocytosis:  
a) caused by hypoxia lung disease; congenital heart defects; abnormal hemoglobins; stay at high altitudes; Pickwickian syndrome (obesity)
b) due to increased erythropoietin production renal cell cancer (formerly hypernephroma); hydronephrosis and polycystic kidney disease; renal artery stenosis; ovarian cancer; cerebellar hemangioblastoma
c) associated with an excess of androgens or adrenocorticosteroid Cushing's syndrome; pheochromocytoma; hyperaldosteronism
Relative erythrocytosis (polycythemia) - due to hemoconcentration: dehydration: sweating, vomiting, diarrhea, burns, diuretic use, alcoholism, stress
Mixed erythrocytosis (polycythemia) - due to thickening of the blood and placental transfusion Physiological polycythemia of the newborn

Reducing the number of red blood cells (less than 4.0 * 1012/L in men and less than 3.7 1012/L in women) - erythropenia - is the main laboratory criteria of anemia. Less erythropenia observed due to the increased volume of circulating plasma (pregnancy, albuminosis, hyperhydration).


Hemoglobin (HGB)

Increasing the concentration of hemoglobin (more than 160 g/L in men and more than 140 g/L in women) can be observed at erythremia and symptomatic erythrocytosis (see. Erythrocytoses (polycythaemias)), related to different states.

Reduced hemoglobin concentration (less than 120 g/L for men and less than 110 g/L in women) in the blood is a major symptom of anemia laboratory.

Depending on the concentration of hemoglobin there are three degrees of severity of anemia:

  • mild anemia (HGB >90 g/L)
  • moderate anemia (HGB 70-90 g/L)
  • severe anemia (HGB < 70 g/L)


Hematocrit (HCT)

Hematocrit (HCT) - the volume fraction of erythrocytes in whole blood; and its value depends on the number and shape. It is calculated as the ratio of the volume of red blood cells to whole blood volume.

Diagnostic significance of the hematocrit value is similar to unidirectional changes in the content of erythrocytes in the blood.

Increased hematocrit values of more than 48% in men and more than 42% for women observed observed in erythrocytosis, decrease below 40% in men and 36% women - observed in anemia and an increase in circulating blood volume (pregnancy, hyperproteinemia, hyperhydration).


Mean corpuscular volume (MCV)

Increased mean corpuscular volume (above 100 fl, macrocytosis) is observed in:

  • megaloblastic anemia (deficiency of Vit. B12 and/or folic acid)
  • anemia after acute hemorrhage
  • some chronic hemolytic anemia
  • aplastic anemia
  • myelodysplastic syndrome (MDS)
  • hypothyroidism
  • liver diseases
  • hemoblastoses and dissemination of malignancies
  • alcoholism
  • taking anticonvulsants, oral contraceptives, cytostatics

Reduced mean corpuscular volume (less than 80 fl, microcytosis) is observed in:

  • iron deficiency anemia
  • anemia of chronic disease
  • thalassemia
  • myelodysplastic syndrome (MDS)
  • lead poisoning
  • impairment of porphyrin synthesis


Mean corpuscular hemoglobin (MCH)

The mean corpuscular hemoglobin in erythrocytes is calculated as the ratio of hemoglobin (g/l) to the number of red blood cells (*1012/L). By MCH values anemia can be divided into hypochromic, normochromic and hyperchromic.

Hyperchromia, i.e. increasing MCH, depends solely on the increase of erythrocyte volume and not from increased saturation of his haemoglobin (see macrocytosis).

Hypochromia may be due to a decrease in red blood cell volume (see. microcytosis) or unsaturated normal volume red blood cells by hemoglobin (iron deficiency or iron-refractory, ie, iron undigested by normoblasts, leading to impaired synthesis of heme (thalassemia, etc.).


Mean corpuscular hemoglobin concentration (MCHC)

Mean corpuscular hemoglobin concentration (MCHC) is calculated as the ratio of hemoglobin (g/dL) to hematocrit (%) and multiplied by 100. The differences between the last two indices is that the MCH indicates the weight of hemoglobin in a single erythrocyte and is expressed in fractions of a gram (picogramme), and MCHC indicates the concentration of hemoglobin in one erythrocyte, i.e., the ratio of hemoglobin to the volume of the cell.

Decreases in MCHC observed in diseases associated with impaired synthesis of hemoglobin.

Increased MCHC above 38 g/dL is rare (congenital spherocytosis). Most often, an increase in this parameter indicates the errors in sample measurements.


Red cell distribution width (RDW)

Red cell distribution width (RDW) characterizes the degree of differences in volume of red blood cells (ie Anisocytosis), calculated by the standard deviation of the red blood cell volume and mean corpuscular volume (MCV).

Increasing the value of red cell distribution width (RDW) signifies heterogeneity of the erythrocyte that occurs more often with anemia.


Red blood cell morphology

In healthy people red blood cells are about the same size, the correct rounded shape, a smear evenly painted in pink with enlightenment in the center (normochromic). This is because of the peculiar form of the erythrocyte in the form of a biconcave disk.

The change of morphology of red blood cells in the form of appearance of erythrocytes of different size (anisocytosis), shapes (poikilocytosis), different color (anisochromia), assorted colors (polychromatophilia) are an important morphological symptoms of various forms of anemia.

The red blood cells mixed with blue tint and differing in color from the majority of surrounding cells are called polychromatophilic. Normally they are absent and they release into the blood occurs with enhanced erythropoiesis (hemolytic anemia, acute blood loss, severe anemia adequate therapy) and dyserythropoiesis (megaloblastic anemia, thalassemia, acute erythroleukemia).

The appearance of basophilic inclusions in red blood cells (the blue dots in the cytoplasm) is associated with proteins coagulation and is characteristic for different types of dyserythropoiesis: thalassemia, hemoglobinopathies, megaloblastic anemias, myelodysplastic syndrome, and lead intoxication.

Red blood cells with remnants of nuclei, Cabot rings and Howell-Jolly bodies — found in marked dyserythropoiesis, in particular, megaloblastic anemia, thalassemia, acute erythroleukemia. Howell-Jolly bodies also found in patients after splenectomy.

Red blood cells with nuclei - normoblasts - are found in the blood in different conditions:

  • severe anemia (except aplastic), including thalassemia, massive hemolysis of any etiology, megaloblastic anemia
  • leukemia - acute erythroleukemia, myeloproliferative diseases
  • carcinomatosis - as in bone marrow metastases as well as in response to tumors
  • after splenectomy
  • severe heart failure
On post contrast spinal cord MRI images revealed so called "sugar coating" in patients with leptomeningeal drop metastases or leptomeningeal carcinomatosis.


Poikilocytosis is a change in the shape of red blood cells.

Possible changes in the shape of red blood cells
Clinical cases, conditions
Microspherocytes Hereditary microspherocytic hemolytic anemia, immune hemolytic anemia, red blood cells fermentopathy, microangiopathic hemolytic anemia
Target cells erythrocytes Thalassemia, hemoglobinopathies, liver disease, iron deficiency, postsplenectomy condition
Ovalocytes Hereditary ovalocytes, megaloblastic anemia, iron deficiency anemia
Stomatocytes Hereditary stomatocytosis hemolytic anemia
Sickle erythrocytes Sickle cell anemia
Spiked erythrocytes (acanthocytes) Uremia, severe liver disease, abetalipoproteinemia
Schistocyte (or schizocyte) DIC (sepsis, tumors), uremia, mechanical damage of red blood cells, hemolytic uremic syndrome, effects of drugs and toxins
Teardrop-shaped erythrocytes Extramedullary erythropoiesis (myeloproliferative disorders, myelofibrosis), thalassemia, severe iron deficiency, megaloblastic anemia
Spur-shaped erythrocytes Children (healthy), liver disease, uremia, DIC, carcinomatosis



Reticulocytes are immature red blood cells, which contain the residue of RNA and formed after the loss normoblasts nuclei. The number of reticulocytes in the blood reflects the regenerative properties of the bone marrow.

Increasing the number of reticulocytes observed at enhanced erythropoiesis, caused by hemorrhage, hemolysis, adequate treatment of anemia (iron deficiency, megaloblastic).

The decrease in the number of reticulocytes or their normal content in anemia is typical for any failure of erythropoiesis (with hypoplasia of hemopoiesis of any origin, including acute leukemia and metastatic lesions of the bone marrow and megaloblastic and iron deficiency anemia, anemia in chronic infections and diseases of the kidneys).


Erythrocyte sedimentation rate (ESR test)

Since erythrocyte sedimentation rate (ESR) is mainly dependent on protein changes in the blood, the increase in ESR is observed in all conditions involving inflammation, tissue destruction, and immunization-related increase in the concentration of fibrinogen and globulins (rheumatoid arthritis, ankylosing spondylitis, etc.). Erythrocyte sedimentation rate decreases by erythrocytosis.

Blood indicator
Normal values for men
Normal values in women
ESR, mm/h 2,0-20,0 2,0-20,0


Factors affecting the change in the level of ESR:

- fibrinogen
- immunoglobulins and other globulins
- haptoglobin
- lipids (cholesterol)
- erythropenia
- anti-erythrocytary antibodies
- alkalosis
- bile acids and pigments
- acidosis
- erythrocytosis (polycythemia)
- anisocytosis of red blood cells
- sickle cell
- erythrocyte spherocytosis