Red cell survival can be measured accurately in humans using enumeration of biotinylated red cells. The method is practical and does not expose the patient to radiation.

Circulating red cell volume measured by the use of biotin with either 125I-streptavidin or flow cytometry agrees with that measured by 51Cr. Each system provides a method of performing these studies without exposing the subject to radiation.

Biotinylation does not render RBCs reactive with normal human plasma (i.e., presumably does not evoke neoantigens). Transfused B-RBCs occasionally provoke IgG antibodies in healthy subjects. Because the biologic effects of B-RBC antibodies currently are unknown, testing for them is recommended when multiple B-RBC transfusions are given to study RBC volume or circulating kinetics.

Using RBCs labeled with two different densities of biotin, RBC volume can be accurately measured simultaneously and repeatedly in the same subject without radiation exposure.