Red blood cell membrane and serum sialic acid in relation to erythrocyte sedimentation rate.

Sialic acid was determined in red blood cell (RBC) membrane and in serum, and correlated to erythrocyte sedimentation rate (ESR). For this purpose blood samples were obtained from 57 patients, regardless of their pathological condition, and divided into groups according to the ESR. 15 blood samples obtained from health individuals whose ESR was lower than 20 mm/h served as controls. Sialic acid was released from RBC membranes obtained by hemolysis, and from serum glycoproteins precipitated with ethanol by treatment with 0.1 N HCl at 80 degrees C for 1 h. The results showed the sialic acid contents of both membranes and serum to be higher in most of the groups with elevated ESR, as compared to the control group, although no quantitative correlation was noticed. Statistical evaluation showed highly significant differences between the group of pathological samples as a whole and the control group in the sialic acid content of both RBC membranes and sera.