A method is described for the determination and charting of the fragility of the red blood cells to hypotonic sodium chloride solution. For plotting the results obtained, a new method was used, employing the principle of "hemolytic increments," i.e., plotting the additional amount of hemolysis occurring in each successive tube of solutions of decreasing saline concentration.
By this method, curves are obtained somewhat similar to those of Price-Jones curves of red cell diameters. Such curves, when properly analyzed, afford an interpretation of the varying diameter thickness range of the red cell population and indirectly an insight into the types of red cells present, and of the possible hemolytic mechanisms present. Preliminary investigations indicate that they are particularly instructive in the hemolytic anemias and especially in the Mediterranean anemias.
A simplified shorter method was also devised for routine clinical use. This method, although not as useful for research purposes, has proved to be more accurate and yet less time consuming than most methods currently used.