RDW – red cell anisocytosis index, it is calculated as the coefficient of variation of the average volume of red blood cells (normal 11.5 – 14.5%). RDW describes the fluctuations of red blood cells and detected by the device much more accurately than by visual viewing a blood smear. A number of errors accompany score anisocytosis under the microscope. After drying of red blood cells in a smear their diameter is reduced by 10-20% in thick smears, he is less than subtle. Completely get rid of the artifacts can only automated counting of liquid blood, in which stability is, preserved cells.
RDW is an important additional criterion for the diagnosis and follow-up results for patients with anemia.
Consider the diagnostic value of this parameter for monitoring the most common type of anemia – iron deficiency anemia (IDA). Hematological parameters depend strongly on the stage of IDA. Thus, in the early stages of this type of anemia red blood cells is normal, and hemoglobin content can be at the lower limit of normal or reduced, reflecting the proliferative activity of normal bone marrow. Erythrocyte histogram is broadened somewhat and begins to shift to the left, RDW is increased.
As violations hemoglobin recovering a reduction in MCV, MCH, ICSU, an increase in RDW. Erythrocyte histogram is considerably broadened and significantly shifted to the left.
The treatment of iron deficiency anemia with iron results in the normalization of hemoglobin concentration, MCV, MCH, ICSU.
In this case, due to appear in the blood of normal population and the young forms RDW continues to increase, the base of the erythrocyte histogram shifted to the right, and the curve itself has two peaks, one of which is located in micro erythrocytes, and another – in the zone macro erythrocytes.
Gradually, the peaks in the red cell histogram are erased, the base shrinks and its histogram takes the normal form. Note that the last hematological parameter, which is normalized upon successful treatment of anemia, is the RDW. Changes in hematological parameters are correlated with the level of the main indicators of iron metabolism (serum iron content, ferritin, total iron binding capacity).
In addition to iron-deficiency anemia, erythrocyte histogram with two peaks of red blood cells between 50 and 140 vials, indicating the presence of a heterogeneous population of cells that may occur after blood transfusions.
RDW blood test high – According to some foreign authors in several cases of iron deficiency anemia RDW is higher than normal earlier than changing the other parameters (MCV and hemoglobin). Invited to an isolated increase in RDW regarded as an early prognostic sign of iron deficiency (DD Bess man, 1989; Win Trobe MM, 1993). In addition, this indicator can assist in the differential diagnosis of microcytic anemia. Thus, patients with low b-thalassemia, the low level of MCV, RDW index is usually normal, whereas in iron deficiency MCV – low and RDW – high.
The use of modern hematology analyzers to quickly and with greater accuracy than with chiropractic methods to assess the state of the hematopoietic system, determine the direction further research, assess the dynamics of changes of red blood cells in the process of therapy.