“…When small volumes of blood need to be frozen (mainly for future serological tests), droplet freezing, a method for RBC preservation in small, individual droplets is common. This technique minimally affects RBC antigenicity [50], while the recovery of polyvinylpyrrolidone supplemented RBCs is acceptable [51]. Last, but not least, freeze drying (lyophilization) of RBCs has been suggested as an alternative way to overtake problems like the complicated transportation of frozen samples.…”