Whole blood storage solution for erythrocyte sodium and sodium-lithium countertransport rate determination.

A solution consisting of heparinized and buffered isosmolar magnesium chloride is described in which whole blood may be stored for preservation of erythrocyte sodium (Na) and membrane sodium-lithium countertransport (Na-Li CT). Correlation (r) of fresh versus 24-h stored erythrocytes for Na was 0.990 (y = 0.30 + 0.956x) and for Na-Li CT was 0.995 (y = -0.014 + 1.022x). Na-Li CT rate was preserved in the storage solution for up to five days and erythrocyte Na concentration for at least 24 h. The solution should find application in epidemiological studies of erythrocyte Na and Na-Li CT rate in human essential hypertension as the blood specimens require no centrifugation or erythrocyte washing procedures prior to laboratory analysis.