Standardization and Application of the Osmotic Fragility Curve to Help in the Anemia Diagnosis

Abstract

At the Osmotic Fragility Curve the erythrocytes are submitted to crescent concentrations of sodium chloride, and the hemolysis percent is available by the quantity of free hemoglobin in solution. Increased resistance occurs in globular anemia and thalassemia, and decreased resistance, in hereditary spherocytosis associated with spherocytosis and hemolytic anemia. This research objective was to standardize the curve according to need and incubation time, to characterize curves of anemic patients and test its efficiency in a blind study, helping on anemia´s characterization. Total blood was collected from individuals distributed in three different search groups: 1) 15 healthy individuals; 2) 15 individuals with hemograms showing microcytosis, spherocytosis, macrocytosis, target erythrocytes, sickle erythrocytes, a left shift and toxic granulation; 3) 10 individuals with altered hemogram (blind study). The blood was pipetted in tubes with a solution of sodium chloride 1% and distilled water. After centrifugation, the reading of the supernatant at 540 nm was performed. The curves of group 1 were done with and without incubation of 24 and 48 hours at 37 °C. In standardization, no difference was observed in the curves with the absence and presence of incubation. In the case of macrocytosis, microcytosis and presence of hemoglobin S, the curve was evident; there were no alterations in the curve with a left shift, toxic granulation and elliptocytes. It was observed that there is no need for incubation execution. The method is useful when associated with hemogram to help in the characterization of megaloblastic anemia, iron deficiency anemia, presence of HbS and thalassemia.