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Effect reduced levels of vitamin B12 and folic acid on the morfology of erythrocytes
POPELOVÁ, Michaela
The morphology of erythrocyte is an important diagnostic element. Changes in morphology can point to certain diseases. Among various morphological features of erythrocytes the automatic analyzers commonly examine their size and stainability. The size of erythrocyte is ranging between 6.7 and 7.7 mmicrometrů. The smaller erythrocytes are called microcytes while bigger ones are called macrocytes. The size of erythrocytes is assessed by MCV (Mean Cell Volume), which indicates the average corpuscular volume. The supply of substances such as proteins, vitamins and minerals is important for proper development and metabolism of erythrocytes. Especially iron, vitamin B12 and folic acid are substances that affect the morphology of the erythrocyte. Deficiency of these substances leads to morphological changes in the blood picture. The deficiency of iron is presented in the peripheral blood like microcytosis (MCV <80 fl). The macrocytosis is the opposite change, which means deficiency of vitamin B12 and folic acid (MCV> 97 fl). This change is the main theme of project. As a result of deficiency of vitamin B12 and folic acid, changes in bone marrow are formed in addition to changes observed in the peripheral blood. Deficiency of vitamin B12 causes the megaloblastic reconstruction of bone marrow. This reconstructed bone marrow differs from normoblastic bone marrow by size, shape and and the gap between the cytoplasm and nucleus maturation. The retardation of nuclear maturation is caused by a suppressed formation of DNA related to the above mentioned deficiency of vitamin B12. Megaloblastic anemia and pernicious anemia are other hematological diseases caused by deficiency of vitamin B12. These diseases are at work also mentioned. The causes, which lead to a lack of both vitamins, are variable, for instance their insufficient food intake, or a defect in their assimilation. At present automatic analyzers offer a full range of tested parameters of blood cells. The samples were examined by an automatic analyzer Coulter LH 750, which operates on the principle of impedance. The value of MCV analyzer calculates using the software as the average of all measured impedance pulses. The macrocytosis was presented in 4% of the total number of samples examined for levels of vitamin B12. In 52% of samples deficient values of B12 (< 150 ng/l) content were observed. The macrocytosis was present in 7.5% of the total number of samples examined for level of folic acid. The deficit values of folic acid (< 3,1 microgram/l) were observed in 38% of all cases. At increased values of MCV 27% deficiency of vitamin B12 and 33% deficiency of folic acid was found. This work confirmed the link between lack of vitamin B12 and folic acid and the subsequent development of morphological changes. The deficiency in vitamin B12, in folic acid or in both vitamins occurred at high MCV.
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