Hemoglobin

Hb - the main component of erythrocytes, is a complex protein consisting of heme and globin. The main function of Hb is to transfer oxygen from the lungs to the tissues, as well as to remove carbon dioxide from the body and regulate CBS.The reference values ​​of the concentration of Hb in the blood are presented in Table.[Titz N., 1997].

Determining the concentration of Hb in the blood plays a crucial role in the diagnosis of anemia. The conclusion about the presence of anemia is based on the results of determining the concentration of Hb and the value of Ht in the blood: for men, the concentration of Hb is lower than 140 g / L and the Ht value is less than 42%;for women - less than 120 g / l and 37% respectively. In anemia, the concentration of Hb varies widely and depends on its shape and severity. In iron deficiency anemia in most patients, the decrease in Hb is relatively moderate( up to 85-114 g / l), less pronounced( up to 60-84 g / l).A significant decrease in the concentration of Hb in the blood( up to 50-85 g / l) is characteristic for acute blood loss, hypoplastic anemia, hemolytic anemia after hemolytic crisis, vitamin B12-deficiency anemia. Concentration Hb 30-40 g / l - an indicator of severe anemia, which requires urgent measures. The minimum concentration of Hb in the blood, compatible with life, is 10 g / l.

The concentration of Hb in the blood can increase( up to 180-220 g / L and above) in myeloproliferative diseases( erythremia) and symptomatic erythrocytosis accompanying various conditions. Changes in Hb concentration for various diseases are presented in the table. The study of Hb concentration in dynamics gives important information about the clinical course of the disease and the effectiveness of treatment. A false increase in Hb concentration in the blood is observed with hypertriglyceria, leukocytosis above 25.0x109 / L, progressive liver disease, hemoglobin C or S, myeloma or Waldenström disease( the presence of readily precipitating globulins).

Table Diseases and conditions accompanied by changes in blood Hb concentration

Table Diseases and conditions accompanied by changes in blood Hb concentration

Several types of Hb are present in human blood: HbA1( 96-98%), HbA2( 2-3%), HbF(1-2%), differing in the amino acid composition of the globin, physical properties and affinity for oxygen. HbF prevails in newborns - 60-80%, by the 4-5th month of life its quantity decreases to 10%.HbA appears in a 12-week-old fetus, in the adult it is the bulk of Hb. HbF in a concentration of up to 10% can be detected with aplastic, megaloblastic anemia, leukemia;with a large p-thalassemia, it can be 60-100% of the total Hb, with a small - 2-5%.Increase of HbA2 fraction is characteristic for p-thalassemia( for large p-thalassemia - 4-10%, for small - 4-8%).

The appearance of pathological forms of Hb is due to a disruption in the synthesis of globin chains( hemoglobinopathies).The most common hemoglobinopathy is S-sickle-cell anemia. The main method for detecting pathological forms of Hb is the method of electrophoresis.