Morphological heterogeneity of individual fresh and stored RBCs. (a) Representative image of normal, fresh RBCs. (b) Representative image of RBCs stored for 6 weeks (2–6°C, AS-1 additive solution). Scale bars are 10 μm. (c) Morphological transformation of stored RBCs: discocyte (D), echinocyte 1 (E1), echinocyte 2 (E2), echinocyte 3 (E3), sphero-echinocyte (SE), stomatocyte 1 (ST1), stomatocyte 2 (ST2), spherocyte (S), ghost (G).