Health, Medicine
In the blood test, RDW is raised or lowered - what does this mean?
When a blood test is done, not only the number of its cells is evaluated, but also their quality. Such characteristics as color, shape, size, too, are important in the diagnosis of diseases and are sometimes the only pathognomonic symptom of the disease. Therefore, hematologists are asked in the laboratory to indicate in the analyzes also RDW, which is deciphered, as the distribution of red blood cells in size.
What it is?
If the doctor can predict that the patient's cell volume may change, he orients it to a general blood test. RDW at the same time the lab worker exposes himself. This is especially true if there is anisocytosis in the blood.
What does RDW mean in a blood test? This is the very violation of the distribution of red blood cells in size.
Anisocytosis is a pathological change in the size of erythrocytes. Normally, it varies from seven to seven and a half micrometers. Microcysts have a value of up to 6.9 micrometers, and macrocytes, respectively, from eight to twelve micrometers. Cells of a larger size can not pass through the diameter of the capillary, therefore they are utilized in the spleen. In a healthy person, the ratio of normal and altered erythrocytes varies between 5: 1. Clinically anisocytosis is manifested by anemia, heart failure, dyspnea, cyanosis. The reasons for the development of this condition may be a lack of vitamins, especially B12 and A, lack of iron, disruption of the red bone marrow, such as myelodysplastic syndrome or the presence of metastases in it with blood cancer. Treatment depends on the cause and is reduced to its elimination.
Assignment of analysis
Usually RDW in the blood test is determined together with other indicators at the initial stage of the diagnosis. This study can be scheduled as planned, during the patient's enrollment in a medical institution, as well as urgently, before surgical interventions. In addition, some patients with the definition of RDW do regularly, to track the dynamics of treatment for blood diseases.
If the result is positive, the doctor will necessarily appoint a second trial, since under the influence of external minor factors, a false positive test can be diagnosed on RDW.
UAC and RDW
There may be a reverse situation, when MCV is higher than the put mark, and RDW is again normal. This combination is noted for liver disease. But the latter is characterized by a peculiar biochemical picture of the blood and coagulogram, so that it is not difficult to carry out differential diagnostics for a qualified doctor.
Research Methodology
If the analysis is positive, then according to the protocol it is necessary to repeat it in order to avoid a false positive result. This rule applies to virtually all tests performed related to the diagnosis of anemia, since the motility of the blood picture gives the doctor an opportunity to question the correctness of the chosen treatment tactics and to review the methods for correcting this pathological condition.
Normal performance
Given the characteristic of the RDW index, one must remember that this parameter does not depend on the size of the cell itself. This can give false-negative results, and is associated with the fact that a large number of red blood cells are present in the blood. Such red blood cells are called macro-cells. Sometimes, in order to accept the results of the analysis as the norm, it is necessary not only to match RDW, but also to correlate it with MCV.
Increased performance
Iron-deficiency anemia
Since iron deficiency anemia is the most common in our hemisphere, we will dwell on it in more detail.
At the first stage of the disease, the number of shaped elements is within the normal range, but the level of hemoglobin in them reaches the lower limit or falls strongly. This gives reason to diagnose anemia. But in the analysis of blood RDW will be normal, since there is no anisocytosis, and the bone marrow is working normally.
The next stage is characterized by an even greater drop in hemoglobin and the number of red blood cells, but other indicators are now changing. RDW in the blood test is increased, there are deviations in the volume of cells, the content of hemoglobin in them and its concentration. The histogram will be strongly shifted to the left.
After the treatment, under the control of blood composition, the amount, volume and shape of red blood cells comes back to normal. This is achieved by taking iron preparations.
Decrease in the indicator
In any case, do not sprinkle the head with ashes ahead of time. In the analysis of blood (RDW), inaccuracies can be allowed, since it makes the machine and it is necessary to recalculate manually. In addition, abnormalities can occur after a blood transfusion or surgical intervention. Then you need to repeat the analysis later.
The picture of blood changes fast enough, so do not panic. It is necessary to show the analysis to your attending physician and listen carefully to his recommendations. This will help to avoid misunderstandings in the future. In addition, each laboratory has its own indicators in the analysis of blood - RDW, depending on what equipment they use. The doctor can refer you to that diagnostic center, the results of which he trusts. This is also very important for the diagnosis.
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