Cryohemolysis, erythrocyte osmotic fragility, and supplementary hematimetric indices in the diagnosis of hereditary spherocytosis

Abstract

BackgroundHereditary spherocytosis (HS) is a chronic hemolytic anemia characterized by microspherocytes in the peripheral blood and increased erythrocyte osmotic fragility (EOF). This study evaluated the cryohemolysis test (CHT); initial hemolysis (IH); immediate and incubated hemolysis percentage in 5.5 g/L NaCl (H5.5); mean corpuscular hemoglobin concentration (MCHC); red blood cell distribution width (RDW); and Hb/MCHC, Hb/RDW, and MCHC/RDW ratios for the diagnosis of HS.MethodsData from 13 patients with HS were evaluated at the Instituto de Bioquímica Aplicada and compared with data from 14 unaffected individuals and 11 patients with anemia due to another etiology. Total blood and reticulocyte counts, CHT, and immediate and incubated EOF were performed in all subjects; sensitivity, specificity, efficiency, and Youden index (YI) were calculated.ResultsEight patients with HS had MCHC ≥345 g/L, 10 had RDW ≥14.5%, 12 had IH >5.0 g/L, 11 had immediate H5.5 ≥5%, and 13 had incubated H5.5 ≥50% (the cut-off value to consider HS). The efficiency and YI were: immediate H5.5 (0.94–0.85), incubated H5.5 (0.89–0.82), IH (0.89–0.78), MCHC (0.87–0.62), CHT (0.84–0.54), and Hb/MCHC (0.71–0.56), respectively. The calculated ratios could distinguish subjects with HS from unaffected individuals (P<0.05), but not those with anemia of another etiology (P>0.05).ConclusionAlthough the CHT and supplementary hematimetric indexes were useful to differentiate individuals with SH from healthy controls, they cannot distinguish from anemias of other etiology. CHT and MCHC, in addition to EOF, are recommended for diagnosing HS patients because of their low cost and efficiency.

Old and new insights into the diagnosis of hereditary spherocytosis

“…Although it represents a sensitive assay which would perfectly complement extended CBC analysis, it has one important limitation (40). As flow cytometers are not available in all routine diagnostic laboratories, FCOF cannot be introduced as a screening test for HS in the international guidelines (41). There are two other tests based on measurement of the osmotic fragility and deformability of RBCs, the cryohemolysis test (CHT) and osmotic gradient ektacytometry test.…”

“…utility of the CHT is disputable, as the sensitivities and specificities obtained in several studies differ significantly, making this assay unreliable(37,41,(43)(44)(45)(46). Ektacytometry determines the deformability of cells at a constant shear stress but gradually changing osmolality, which depends on the inner viscosity, volume-to-surface area and viscosity of the cell membrane(47)(48)(49).…”

ErythrocytesÓ? osmotic fragility test with a standard Abbe refractometer

“…In summary, we illustrate in this work the viability of simple and rapid procedure to determine the standard OF curve of blood samples and provides information related to the integrity of the erythrocyte membrane, which can be an indicator of the health status of people associated with different pathologies such as: thalassemia 15,16 , macro or micro spherocytosis 17,18 , and paroxysmal nocturnal hemoglobinuria 19,20 , among others 21 . One of its main advantages over other techniques such as flow cytometry is that it is a rapid and economical test so that it does not require large material resources and can open the way to develop new robust instruments for the early detection of different blood pathologies.…”

Phytocomponents from Anacardium occidentale, Psidium guajava, and Terminalia catappa altered membrane osmotic stability of sickle erythrocytes

“…Accordingly, osmotic fragility index defines the capacity of the erythrocytes to withstand hemolysis when subjected to osmotic stress [27]. Osmotic fragility test, in which the population of hemolyzed erythrocytes is measured as a function of variability in osmolality of erythrocyte suspension, is primarily diagnostic of hereditary disorders of erythrocyte membrane cytoskeletal structures such as hereditary spherocytosis and other vast groups of the hemolytic anemias [27][28][29][30][31][32]. The extrinsic and intrinsic factors that influence erythrocyte osmotic fragility index are summarized elsewhere [27,30].…”