A blood test for erythrocyte osmotic resistance (RBC) is rarely prescribed. This examination is usually performed when hemolytic anemia is suspected. The assay helps determine the life cycle and persistence of the red blood cell membrane. This diagnosis is usually prescribed by hematologists. The study can be done not in all laboratories. WSE is done in special centers for the study of blood diseases, as well as in some paid laboratories ("Veralab", "Unilab", etc.) INVITRO does not determine the osmotic resistance of erythrocytes.
What is WEM
WRE is the resistance of red blood cells to destructive factors: high or low temperature, chemicals, as well as mechanical stress. Resistance is usually detected in laboratory experimentsred blood cells to sodium chloride (NaCl). During the experiments, it is important to find out what concentration of this chemical causes the destruction of red blood cells. This helps to reveal the resistance of blood cell membranes to pressure and the chemical effects of saline solution (osmosis). Normal red blood cells may resist. They remain strong, and their shells remain intact. This is called the osmotic resistance of red blood cells.
The immune system is able to detect blood cells that are weak and cannot resist the attack. Over time, these red blood cells leave the body.
How WEM is researched
To determine the osmotic resistance of erythrocytes, the reaction of blood and sodium chloride solution is monitored. These ingredients are mixed in equal proportions.
If the concentration of sodium chloride solution is 0.85%, then it is called isotonic (or saline). At a lower s alt content, the chemical is called hypotonic, and at a higher s alt content, it is called hypertonic. In an isotonic solution, erythrocytes do not break down, in a hypotonic solution they swell and disintegrate, and in a hypertonic solution they shrink and die.
How the analysis is done
The method for determining the osmotic resistance of erythrocytes is associated with the use of hypotonic solutions with a concentration of 0.22 to 0.7%. The same amount of blood is placed in them. This mixture is kept for about an hour at room temperature, and then subjected to processing incentrifuge. At the same time, the color of the liquid is observed. At the beginning of the process of erythrocyte breakdown, the mixture becomes slightly pink, and when the blood cells are completely destroyed, it turns red.
Thus, when determining the osmotic resistance of erythrocytes, 2 indicators are obtained: minimum and maximum.
This test helps determine the cause of anemia. The patient's blood is taken from a vein. No special preparation or diet is required prior to testing.
Resistance rate
The norm of the WEM indicator does not depend on the age and gender of the patient. A slight decrease in this value is observed in the elderly, and an increase in children under 2 years old.
The norm of osmotic resistance of erythrocytes is considered to be the maximum indicator - from 0.32 to 0.34% and the minimum - from 0.46 to 0.48%.
This means that normal erythrocytes show the greatest stability in a solution with a concentration of 0.32 - 0.34%, and the least - in 0.43 - 0.48%.
Reason for rejection
In some cases, the WEM may be above or below the norm. An increase in the resistance of red blood cell membranes is observed in hemolytic jaundice. In this case, an increase in bilirubin occurs, and cholesterol is deposited on the membranes of red blood cells. And also an increase in the ORE occurs with abnormalities of the erythrocyte membrane (spherocytosis) and with a violation of the structure of hemoglobin (hemoglobinopathies).
Decrease in osmotic resistanceRBC occurs in the following cases:
- Blood diseases, removal of the spleen, massive blood loss.
- Cardiovascular pathologies. At the same time, red blood cells are shaped like a sphere and have poor resistance to external influences.
- Genetic anomalies in which red blood cells are shaped like balls. These altered cells have low resistance.
- A large number of old red blood cells, with high membrane permeability. This may be due to kidney disease. It is this organ that is responsible for removing old blood cells from the body.
However, you need to remember that with some types of anemia, the WEM indicator may remain normal. For example, if the activity of the erythrocyte enzyme (G-6-PDG) is insufficient, the result of the analysis will be within acceptable limits. But at the same time, the patient has all the signs of anemia.
Norm limits
In the study, the boundaries of the osmotic resistance of erythrocytes are determined. Exceeding or decreasing these indicators may mean pathology.
The upper limit of the WEM is normally no more than 0.32%. If resistance becomes less than this indicator, then this may indicate the following pathologies:
- hemoglobinopathy;
- congestive jaundice;
- spleen removal operation;
- thalassemia;
- polycythemia;
- severe blood loss.
If the lower limit of osmotic resistance of erythrocytes becomes more than 0.48%, then this may be with different types of hemolyticanemia and after lead poisoning.
With some types of blood pathologies, the boundaries of the WEM may expand. This happens with anemia associated with vitamin B12 deficiency and the destruction of red blood cells during an acute hemolytic crisis.
Shape and maturity of red blood cells
The osmotic resistance of erythrocytes depends on the shape of these cells. The resistance is much lower in red blood cells, which have a pronounced spherical or spherical shape. Such cells are very susceptible to destruction under the influence of various factors. The shape of red blood cells can be hereditary or a consequence of their aging.
The stability of red blood cells is also affected by their age. The highest resistance is found in young cells that have a flat shape.
Signs of violation of WEM
When there are deviations in the analysis for WEM, the well-being of patients always changes. Patients complain of the following symptoms:
- fatigue;
- general breakdown;
- drowsy state, constant desire to lie down;
- pale skin;
- loss of appetite;
- unreasonable rise in temperature;
- weight loss.
Such manifestations are the result of oxygen starvation of tissues. Usually, with deviations in the analysis of the ORE, the doctor prescribes additional studies to clarify the cause of the pathology. If the disorders are not the result of a genetic disease, then after a course of therapy, red blood cells return to normal.
Whenviolations of erythrocyte resistance, patients are prescribed corticosteroid hormones, vitamins (folic acid), drugs containing iron. In severe cases, with frequent exacerbations of the disease, a surgical operation is performed to remove the spleen.
Specific prevention of erythrocyte resistance disorders has not been developed. Many types of such deviations are hereditary. Such patients require a consultation with a geneticist so that patients do not pass on the pathology to their children. We also need preventive measures to prevent the development of a hemolytic crisis. Patients need to provide conditions for good hematopoiesis. It is necessary to take vitamins and drugs to prevent anemia, as well as a diet with sufficient iron content. This will help avoid exacerbation of hemolytic manifestations, and in some cases improve the results of the WEM analysis.
