Osmotic resistance is the capacity of a cell to survive in a medium Hypotonique.

When two solutions of different concentrations out of salts are separated by a semipermeable membrane , the concentrations tend towards balance by passage of solvent of the solution the least concentrated towards the most concentrated solution, like showed it Henri Dutrochet at the time of the description of the Osmose. The necessary pressure likely to be opposed to this passage measures the osmotic Pression. This pressure thus depends on the concentration of the solution.

Cell, whose cytoplasm is an aqueous solution, placed in an aqueous solution less concentrated, will fill of water, which will cause an internal pressure, known as osmotic pressure. If the cellular membrane resists this pressure, we arrive at a balance, and the cell survives. If the membrane does not resist, the cell bursts and disappears. It is cellular death or Cytolyse.

Description

In hematology, the osmotic resistance of the Hématie S is appreciated by putting the same quantity of blood heparinized or Défibriné in plugged saline solutions, with concentration decreasing saltworks. At the end of one hour, one measures in each tube the quantity of released hemoglobin and one expresses it in % of total hemoglobin present in blood. One obtains thus, for each concentration saltworks, the percentage of Hémolyse. One carries in graph (ordered) these percentages compared to the concentrations saltworks (X-coordinates). A characteristic curve sigmoïdale thus is obtained. Although osmotic resistance is pathological to differing degree in acquired haemolytic anemias, the clearest modifications remain clean constitutional sphérocytose, or Maladie of Minkowski-Roadhog.