ABSTRACT
The osmotic fragility test of red cells is essentially a measurement of the extent of redundancy of the erythrocytes’ cell wall, or as expressed by Beutler (1977), it is a simplied means of estimating the surface-volume ratio of erythrocytes. That is, the more redundant a cell’s wall is, the greater is its capability to accommodate to hypotonic solutions. As one might conclude, biconcave-shaped cells (such as the macaque’s or man’s erythrocytes) have a greater redundancy of plasmalemma (an excess of plasma membrane) than spherocytic cells (Figure 28).
