Erythrocyte agglomeration and survival studies in citrate-phosphate-dextrose (CPD) units.

We have previously reported increased tendency to agglomeration in CPD-stored erythrocytes. In the present study we investigated the deterioration pattern of fresh units, as detected by agglomeration, free hemoglobin levels, ATP levels, osmotic fragility, and certain enzymatic activities. When the negative test was converted to a positive one, the 24-h survival values of these units were determined by autotransfusion. A positive agglomeration occurred while viability was still above 70%. Fresh units had high ATP levels and negative agglomeration while old units had low ATP levels and positive agglomeration. However, in intermediate-storage units, no definite correlation between ATP and agglomeration was found. Agglomeration seems to reflect the degree of changes in stored erythrocytes. However, further studies are needed before this test may serve for prediction of post-transfusion viability.