Blood test reticulocytes is a clinical study in which young red blood cells produced by the bone marrow are counted. The study complements the general blood test. Reticulocyte counts are performed for differential diagnosis of various types of anemia, assessment of bone marrow and spleen functioning, monitoring of patients with iron deficiency, vitamin B12 or folic acid deficiency, renal insufficiency, oncological diseases. Blood sampling for the study is performed from a vein or capillaries. The indicator of reticulocytes is determined using the method of flow cytofluorimetry. Reference values for men – 23-70 thousand / ml, for women – 17-63.8 thousand / ml. The timing of the analysis does not exceed 1 working day.
Reticulocytes are the precursors of erythrocytes. They are produced by the bone marrow during the differentiation and division of stem cells. Most of the reticulocytes are located in the bone marrow, mature red blood cells mainly enter the bloodstream. The proportion of reticulocytes in the blood is about 0.5-2%. When performing the analysis, the number of cells of this type and their percentage of the total number of red blood cells are determined. The results of blood tests for reticulocytes allow us to evaluate the production of red blood cells in the bone marrow, to identify the degree of activity of this process.
The body maintains a stable level of red blood cells in the blood. With a decrease in their number as a result of hemolysis, impaired synthesis, bleeding, compensatory mechanisms for restoring normal concentration are activated. By changing the level and percentage of reticulocytes, it is possible to establish an increase in the production of red blood cells in the bone marrow or inhibition of this process. If the bone marrow functions normally, then the loss of red blood cells leads to a subsequent increase in their number and the number of reticulocytes. A decrease in the level of these types of cells occurs when the red bone marrow is affected by a tumor, metastases, radiation therapy and chemotherapy. For the analysis of reticulocytes, the biomaterial is capillary or venous blood. The study is performed using a hematological analyzer by flow cytometry. The results are used in general therapeutic practice, in hematology, pediatrics, infectious diseases, surgery.
Reticulocyte assay is used to evaluate the production of red blood cells by the bone marrow. The results of the study allow differentiating different types of anemia. According to the level of reticulocytes, they are divided into hyporegenerative and regenerative. In the first case, the test parameters are reduced, the production of red blood cells is insufficient, the functions of the bone marrow are suppressed. This group includes hemolytic anemia in chronic diseases, general intoxication, cachexia, deficiency of proteins, iron, vitamins. Regenerative anemia is accompanied by a compensatory increase in the level of reticulocytes against the background of increased destruction or loss of red blood cells. This group includes posthemorrhagic and some hemolytic anemia. A blood test reticulocytes can be used to determine the severity of anemia, then its results are supplemented with indicators of the level of erythrocytes, hemoglobin and erythrocyte indices.
Determination of the level of reticulocytes is indicated with a reduced level of erythrocytes, hemoglobin, with complaints of frequent fatigue, headaches, shortness of breath, blood in the urine or stool. With an established diagnosis of anemia, an analysis is prescribed to assess the effectiveness of treatment. It is especially often used to monitor anemia caused by iron deficiency, vitamin B12 or folic acid, as well as developing against the background of kidney failure, chronic diseases. To study the function of the bone marrow, a reticulocyte test is indicated with an elevated level of red blood cells, to determine the cause of polycythemia.
A blood test reticulocytes is not used to establish a diagnosis. Its main purpose in clinical practice is to plan further diagnostic procedures and monitor the success of therapy. The number of reticulocytes in the blood is relatively stable, therefore, with a decrease in the level of erythrocytes and hematocrit, the analysis indicators become artificially inflated. The calculation of the reticulocyte index – the absolute number of reticulocytes (the percentage of reticulocytes multiplied by the hematocrit index) helps to avoid this. Another feature of this study is that the results indicate recent bone marrow activity, as immature red blood cells have been circulating in the blood for 2 days.
Preparation for analysis and material collection
It is recommended to take blood test reticulocytes in the morning, on an empty stomach. The minimum interval between meals and the procedure is 3-4 hours. At least a day it is necessary to give up intense physical exertion, alcohol consumption, and avoid exposure to stressful factors. When prescribing an analysis, it is worth informing the doctor about the medications used, since some drugs affect the level of reticulocytes in the blood. 30 minutes before the sampling procedure, you need to give up smoking, eliminate physical and emotional stress.
The level of reticulocytes is determined in capillary or venous blood. Accordingly, the fence is made from the ring finger or from the ulnar vein. The blood is placed in a test tube with an anticoagulant and sent to the laboratory. Currently, hematological analyzers are used almost everywhere to count reticulocytes. The study is performed by flow cytometry – cells in the fluid flow move through a very narrow capillary and are taken into account when irradiated with a laser. The deadline for the analysis is 1 day.
The results of the analysis for reticulocytes show the absolute number of cells per unit volume of blood and the percentage of the total number of red blood cells. Normally, in female patients, the level of reticulocytes ranges from 17 *109 to 63.8 *109 cells /l, in male patients – from 23 *109 to 70*109 cells / l. The proportion of cells of this type in the total number of red blood cells varies with age:
- from birth to 2 weeks – from 0.15 to 1.5%;
- from 2 weeks to 1 month – from 0.45 to 1.4%;
- from 2 to 6 months – from 0.25 to 0.9%;
- from 6 months to 2 years – from 0.2 to 1%;
- from 2 to 6 years – from 0.2 to 0.7%;
- from 6 to 12 years – from 0.2 to 1.3%;
- from 12 to 18 years – from 0.12 to 2.05% for girls, from 0.24 to 1.7% for boys;
- from the age of 18 – from 0.59 to 2.07% for women, from 0.67 to 1.92% for men.
A physiological increase in the level of reticulocytes in the blood occurs with oxygen starvation caused by rising to a great height or going under water, prolonged stay in an unventilated room, smoking, alcohol intake. In addition, an increase in the concentration of these cells is sometimes determined in pregnant women and is considered as a variant of the norm.
Raising the level
The cause of an increase in the level of reticulocytes in the blood may be bleeding. The concentration of red blood cells decreases in order to restore it, the bone marrow increases the production of their precursors. With acute bleeding, the number of reticulocytes increases by 3 or 4 days, with chronic bleeding, it remains persistently elevated all the time. In diseases accompanied by hemolysis (destruction of red blood cells), the reticulocyte index significantly exceeds the norm, sometimes deviations reach 300%. The most common pathologies of this group are hereditary defects of red blood cells, their autoimmune destruction, toxic damage in malaria. Other causes of an increase in the level of reticulocytes may be polycythemia, inflammatory processes, bone marrow cancer or the spread of metastases into it, restoration of bone marrow functions after radiation and chemotherapy. In the treatment of anemia, normalization of the concentration of reticulocytes indicates the success of therapeutic measures.
Lowering the level
The reason for the decrease in the level of reticulocytes in the blood may be anemia caused by a deficiency of iron, vitamin B12 or folic acid. In such cases, the production of blood cells is reduced due to a lack of “building material”. Another reason for the decrease in the level of reticulocytes is anemia, which develops against the background of bone marrow lesions or inhibition of its functions. Changes of this type are determined by alcohol intoxication, decreased thyroid activity, chronic infections, autoimmune pathologies, kidney diseases, exposure to toxic substances, including drugs, radiation.
Treatment of abnormalities
In clinical practice, a blood test reticulocytes is most often prescribed after a general blood test with a decrease in red blood cells and hemoglobin. The level of reticulocytes allows you to evaluate the functions of the bone marrow, the synthesis of red blood cells, determine the type of anemia, monitor the effectiveness of its treatment. If the results of the study deviate from normal, it is worth seeking advice from the attending physician, pediatrician, hematologist, surgeon. In order to prevent the influence of physiological factors on the number of reticulocytes, it is necessary to exclude situations that cause oxygen starvation – ascents to heights or descents under water, prolonged stay in a polluted or stuffy room, smoking, alcohol consumption.