Blood substitutes: evolution and future applications.

The development of oxygen-carrying blood substitutes has progressed significantly in the last decade with phase I and phase II clinical trials of both hemoglobin-based and perfluorocarbon-based oxygen carriers nearing completion. As these products approach clinical use it is important for the laboratory medicine community to be aware of their effects on routine laboratory testing and the settings in which they might be used. Here we review the forces driving the development of oxygen-carrying blood substitutes, the clinical settings in which they might be used, the major categories of oxygen carriers in clinical trials, and the challenges faced by these products as they approach clinical use.