Hypoxic storage improved RBC physiological function. (A) Histograms of O2 unloading time constant (top) and O2 carrying capacity (bottom) for bloods in pool C, sampled at various time points indicated during 49-day storage under standard condition (black lines) or hypoxia (red lines). Rejuvenation at 28 day was included as a benchmark (blue lines). Each histogram is constructed from at least 500 cells collected from at least 2 loadings and measurements from 6 fields of view. (B) Histograms of O2 unloading time constant (top row) and O2 carrying capacity (bottom row) for all 6 pools at day 21 of storage. (C) Effect of hypoxic storage and rejuvenation on flow cytometric parameters: FSC (top) and SSC (bottom). Mean of 2 flow cytometric experiments per time point. Star symbols show effect of rejuvenation relative to its control. (D) Average data from 6 pools for physiological and flow cytometric indices. *P < .05; **P < .01 (t-test).