Numrarea eritrocitelor

Erythrocytes Sedimentation Rate (ESR; VSH-abv. Romanian)

Principle:From the collected sample, some blood is mixed with anticoagulant (sodium citrate 3.8%), then aspirated into a pipette (Westergreen pipette) and allowed to stand in a vertical position; red blood cells settle with variable speed.Westergreen technique:Required materiale:- necessary materials for drawing venous blood;- anticoagulant: sodium citrate 3,8%;-Westergreen pipette with milimetrical engravings from 0 to 200;-stand;-stopwatch.

After drawing venous blood and anticoagulation(1,6ml of blood and 0,4ml sodium citrate 3,8%;20% overall dilution), it is aspirated in the Westergreen pipette up to its 0 engraving. The pipette is placed on the stand, perfectly vertical. After precisely one hour the engraving corresponding to the border between the formed plasma and erythrocytes columns is read. The two columns appear due to the difference of density between the plasma and erythrocytes: 1027 and 1039.The sedimentation rate is influenced by the red blood cells ability to group up in rolls (fact which depends on the erythrocytes surface attraction, or zeta potential). The forming of rolls will be influenced by plasmatic and erythrocyte factors.TechniqueSerum factors (plasmatic factors) are represented by the ratio of plasma proteins: the ratio of albumin and globulin and plasma concentration of fibrinogen in the sample. Elevated plasma asymmetric molecules greatly reduces the forces of repulsion between RBCs, thus increasing the concentration of globulin and fibrinogen will ease the layout of erythrocytes in rolls (columns) and accelerating the sedimentation.Erythrocyte factors are represented by the number of red blood cells and by red blood cells and plasma ratio(hematocrit), but also by the changes of erythrocyte surface or shape. Reducing the number of red blood cells will exacerbate ESR while increasing their number, as in polyglobulia, reduce ESR value. Microcytes will settle more slowly than macrocytes and red blood cells of sickle cell disease, sickle-shaped will determine hard rolls and a low ESR.ESR physiological values: 15mm/hour (M) and 20 mm/hour (F).ESR is considered a nonspecific indicator of the state of inflammation, accompanying it is always the altering ratio of albumin and globulin and/or plasma concentration of fibribogen increases. It should be noted that normal ESR does not exclude, however, a level of inflammation. Acute or chronic inflammatory conditions like neoplastic conditions are accompanied by high values of this parameter. Very high values, about 100 mm/hour may suggest the diagnosis of multiple myeloma, collagen diseases, tuberculosis, or cancer.