Deoxyhemoglobin S gelation and insolubility at high ionic strength are distinct phenomena.

Deoxyhemoglobin S in solution forms a solid phase either in solutions of high ionic strength or in solutions of low ionic strength but a high hemoglobin concentrations. Presently, both techniques are in use to study various hemoglobin interactions which might occur during sickling of Hb S-containing red cells. When Hb S is treated with either nitrogen mustard or cyanate, there is no correlation between high-ionic-strength salting out and low-ionic-strength gelation studies. These results suggest that salting out studies are not equivalent to the assays that depend on the gelation of polymerization of Hb S.