Definition of Anemia
المؤلف:
Marcello Ciaccio
المصدر:
Clinical and Laboratory Medicine Textbook 2021
الجزء والصفحة:
p163
2025-06-12
384
Anemia is a blood disorder characterized by a reduced ability of the blood to carry oxygen due to a decrease in the mass of erythrocytes and, therefore, in the oxygen transporter they contain, hemoglobin. Symptoms accompanying anemia are generally dependent on the extent of the reduction of erythrocyte mass, and consequently of hemoglobin, and on the time within which it occurred. Specifically, a slow progression toward anemia is compensated and tolerated up to limits of erythrocyte mass and hemoglobin that would not be tolerated if they were reached in a short time, for example, during massive hemorrhages. In such a compensatory effect, immediate and delayed mechanisms are of great importance. These include the increase in heart rate, peripheral vasoconstriction, and the increase in 2,3-diphosphoglycerate, which is accompanied by the shift of the oxygenation curve of hemoglobin to the right, on the one hand, and by the secretion of erythropoietin, in turn, stimulated by the combined action of the hypoxia-inducible factor (HIF-1, -2), on the other hand.
It is, therefore, a complex picture in which the laboratory plays a fundamental diagnostic role in the identification of the primary causes of anemia (congenital or acquired), in the evaluation of the current status and severity of the anemia, and in the therapeutic follow-up of the anemic patient.
The World Health Organization (WHO), in view of the high incidence of anemia, defined as “low hemoglobin con centration in the blood” according to the values in Table 1, has implemented a series of actions aimed at reducing its global incidence.
Table1. Hemoglobin values (g/L) for the diagnosis of sea level anemia
Indeed, anemia has been shown to be a public health problem that affects low-, middle-, and high-income countries and has significant adverse health consequences as well as negative effects on social and economic development.
Although the most reliable indicator of anemia is the concentration of hemoglobin in the blood, its measurement alone cannot indicate the cause. Anemia can result from several causes, and iron deficiency is the most important. About 50% of cases of anemia are due to iron deficiency, but the percentage probably varies among population groups in different areas depending on the local conditions, primarily the quality of the diet. Other causes of anemia include other micro nutrient deficiencies (e.g., folate, riboflavin, vitamin A, and vitamin B12), acute and chronic infections (e.g., malaria, cancer, tuberculosis, and HIV), and inherited or acquired dis eases affecting hemoglobin synthesis, red blood cell production, or red blood cell survival (e.g., hemoglobinopathies).
الاكثر قراءة في اضطرابات الدورة الدموية
اخر الاخبار
اخبار العتبة العباسية المقدسة
