The íerythrocyte indices They are a compendium of studies done with a whole blood sample to determine the conditions of the red series, which is the cell line corresponding to erythrocytes or red blood cells. The first laboratory test that every patient is asked for is usually a complete hematology or hematic biometry..
This study looks at the three basic cell lines in the blood: white blood cells (leukocytes), red blood cells (erythrocytes), and platelets (thrombocytes). Results for each group of cells can be interpreted individually or together.
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Red cell indices help the doctor and his team to elucidate the etiology and characteristics of anemias.
Through these studies, the differential diagnosis between the different anemic pictures can be made, in addition to performing routine controls on patients with said disease.
They are also useful for diagnosing other types of hemoglobinopathies and hematological diseases, even those of a malignant nature that affect or modify the values of the red blood series..
They are semi-quantitative values provided by the laboratory equipment in which whole blood samples are processed, using methods such as impedance, laser counting or light diffraction. They are the first hematic biometry results to be reported and include:
- Hemoglobin.
- Hematocrit.
- Total number of erythrocytes.
- Reticulocytes.
Direct analysis of these indices makes it possible to determine the presence of anemia or polycythemia.
They are calculated based on the primary indices and guide the physician regarding the characteristics, etiology, and possible treatment of anemia. These include:
- Mean corpuscular volume (MCV).
- Mean corpuscular hemoglobin (HCM).
- Mean corpuscular hemoglobin concentration (MCHC).
Defines the average red blood cell or erythrocyte size in a specific blood sample. It is expressed in fentoliters or cubic microns.
It is calculated using the following formula:
MCV = hematocrit (%) x 10 / total number of erythrocytes
It refers to the amount of hemoglobin found within each erythrocyte or red blood cell. It is expressed in picograms. It is calculated through the formula:
HCM = Hb (gr / dL) x 10 / total number of erythrocytes
Indicates the average amount of hemoglobin per unit volume. Unlike mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration correlates hemoglobin content with erythrocyte size, making this value somewhat more accurate for certain diagnoses..
Its calculation is carried out with the following formula:
MCHC = hemoglobin (gr / dL) x 100 / hematocrit (%)
The results of certain tests may vary according to the laboratory where they are carried out and the equipment used. There are also modifications by race, gender, ethnicity, geographic origin, age and eating patterns that can be important.
The values published in this text are those that have the greatest acceptance and use worldwide, being broad due to the previous considerations..
Among the most important erythrocyte indices we have:
11.5 - 15.5 gr / dL
35 - 46%
4.2 - 6.1 million cells per microliter (cel / mcL)
0.5 - 1.5%.
80 - 94 fentoliters (fL).
26 - 32 picograms (pg).
32 -36 g / dL
Low hemoglobin levels indicate the presence of any type of anemia. Elevated levels mean polycythemia.
Despite being very nonspecific, this measure is essential for the initial diagnosis of any hematological pathology.
It is the percentage of actual hemoglobin per unit volume. Associated with hemoglobin levels, it allows to know if hemoglobin values have been affected by hemoconcentration (loss of fluids) or by hemodilution (increase in intravascular fluid).
The total red blood cell or red blood cell count is helpful in determining whether there is adequate or increased red cell production. It can orient towards spinal or infectious problems although it is very unspecific.
In the presence of an anemic condition, it helps to determine if there is normocytosis (red blood cell of adequate size), microcytosis (small red blood cell) or macrocytosis (large red blood cell). It is of vital importance to determine the etiology of anemias.
- Iron deficiency anemia (due to a decrease in iron in the body).
- Thalassemia minor.
- Sideroblastic anemia.
- For chronic diseases such as kidney failure, diabetes and liver disease (the most common in older adults).
- Hemolytic.
- Aplastic.
- Malignant disease anemia.
- Megaloblastic anemia (due to vitamin B12 or folate deficiency).
They help to identify if anemic pictures are normochromic, hypochromic or hyperchromic, thanks to the staining of the hemoglobin seen under the microscope.
- Iron deficiency anemia.
- Hemolytic.
- Post-hemorrhagic anemia.
- Due to protein malnutrition.
- Aplastic anemia.
- Alcoholism.
- Thyroid diseases.
The reticulocyte count, an immature form of the erythrocyte, is useful in evaluating the production and quality of red blood cells. Some laboratory equipment calculates it automatically, and in some cases they must be specifically requested.
Faced with an anemic condition, the amount of reticulocytes allows us to classify it as regenerative or aregenerative and refers to the productive response of the bone marrow in a scenario of erythrocyte loss.
High reticulocytes = regenerative anemia. For example, hemolysis or acute bleeding.
Low reticulocytes = aregenerative anemia. For example, iron deficiency, aplastic anemia, or vitamin B12 or folate deficiency.
Although erythrocyte indices guide us more in the diagnosis of anemias, we must not forget polycythemias. These blood diseases are characterized by the presence of an elevated hematocrit and, although rare, should be considered.
Polycythemia vera or primary polycythemia is a bone marrow disease characterized by the exaggerated production of erythrocytes without there being a biological need for it. May be accompanied by an increase in white blood cells and platelets.
Other cases of polycythemia can be seen in dehydration, hypoxia, some types of cancer, immune diseases and genetic disorders.
Another important cause is mountain sickness due to the decrease in available oxygen in the air at high altitudes, which causes a compensatory increase in hemoglobin in the blood..
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