The quantitative estimation of the fragility of the red corpuscles

Abstract

Pathologist to The Bland-Sutton Institute, The Middlesex Hospital ; and M. HYNES, B.A., Demonstrator in Pathology, The Bland-Sutton Institute, The Middlesex Hospital.THE decreased resistance of the red corpuscles to relatively high concentrations of saline has long been known as an almost pathognomonic test for htemolytic icterus, whilst the wide application of the fragility test has shown that more information is given by a quantitative determination than by a simple qualitative test. But, except for Simmel (1923), no very detailed accounts of a quantitative technique have been published despite the fact that many authorities emphasise the value of such a method. The ordinary method is briefly thus. Withdraw some blood from a vein into a syringe containing 3.8 per cent. sodium citrate solution, taking 4 parts of blood to 1 part of the citrate. Wash the corpuscles three times in physiological saline and make a 1 in 100 dilution of the packed washed corpuscles in tubes containing concentrations of saline varying from 0.25 to 0.75 per cent. When hEmolysis occurs it is shown by a tinge imparted to the supernatant fluid whilst the degree of hzmolysis can be roughly estimated by comparing the tinges with the naked eye. Obviously the large personal error involved in this method makes the procedure unsuitable for accurate quantitative work.Simmel's technique was a great improvement but his work does not seem to have attracted much notice in this country. Simmel used, instead of saline solution, a solution of salts in the proportions in which they occur in human blood and having the same osmotic pressure as the blood plasma. Dilutions of the stock solution to 30, 40, 50, 60 and 70 per cent. in distilled water were made in order to estimate the fragility of the red cells.Simmel claimed two advantages for his method, firstly that the concentration of the various salts in the hypotonic solutions was proportional to the concentration in normal plasma, and secondly that the solution was well buffered and would therefore have a constant p H . The first point does not seem to us to be of great importance, for there can be no comparison between hEmolysis as 219

The Osmotic Fragility and Density Distribution of Erythrocytes in the Newborn

“…The increase in osmotic resistance generally observed in red cells from cord blood in this study is in contradiction with the increased fragility reported by several authors [8,13]. The data obtained by the 50% hemolysis test are of limited value as can be seen from the considerable amount of overlap in the osmotic resistance values for cord and adult blood at this level of hemolysis ( fig.…”

“…Goldbloom and Gotlieb [8] reported increased osmotic fragility of newborn red blood cells. Whitby and Hynes [13], cited by Wintrobe [14], claimed that the red blood corpuscles of newborn children are somewhat more fragile than those of adults, but did not regard the difference as significant. Waugh et al [12] reviewed 15 papers on the subject and concluded that fetal cells are slightly more resistant.…”

Effects of Primaquine and Other Related Compounds on the Red Blood Cell Membrane. I. Na+ and K+ Permeability in Normal Human Cells*

“…An additional tube containing 1.0 per cent NaCl was included in the fragility test to mimic the additional osmotic effect of the serum protein, and no additional hemiolysis above that found in the serum itself was observed at this concentration of NaCl. Since estimation of per cent hemolysis on the basis of plasma hemoglobin measurements may introduce an error related to the amount of hemoglobin retained by individual hemolyzed or ghost cells, a more specific visual estimate of the percentage of hemolyzed cells was carried out in a manner somewhat similar to the original osmotic fragility studies of Whitby and Hynes (19), who used red blood cell counts. Stained cell preparations were made by placing 50 1l of the experimental cell suspensions into 10 ml of the 0.70 per cent NaCl-PO buffer (pH 7.4) described by and allowing the injured cells to hemolyze during 20 minutes of incubation at room temperature.…”

The Osmotic Fragility of Red Cells in Newborns and Infants

“…The difference in the values of a in the two groups is also highly significant statistically: moreover, there is no overlap between the two. This index effectively 20 …”