[Effect of osmolarity and pH of the medium on the density of red blood cells of newborns and adults].

The influence of osmolarity and pH-value of a buffered saline glucose solution (BSG) on the density of red blood cells (RBC) of human newborns and adults were tested. The median density of RBC increases with increasing osmolarity by 1.2 mg/ml cells per 10 mosmol/l increase of osmolarity. This holds true for newborns and adults. The median density of RBC increases with increasing pH. The density of RBC of newborns increases by 5.7 mg/ml cells per one pH-unit increase, the density of RBC of adults increases by about 10.3 mg/ml cells per one pH-unit increase. These differences are probably caused by different physical-chemical properties of HbF and HbA.