In summary, red cell carbohydrate metabolism plays an important role in the cell, both for maintaining cell viability through ATP and for maintaining proper oxygen release through DPG. These functions are compromised by traditional liquid storage. Frozen storage maintains these functions for an indefinite period of time. However, the cells are not metabolically perfect, at least with current techniques, and assay of glycolytic intermediates is a useful monitoring device to evaluate the effects of various manipulations, particularly after thawing and washing have taken place.