Long-term storage of blood in liquid nitrogen, and the response of the recovered red cells to haemagglutination by viruses.

Human and chicken blood were snap-frozen as droplets in liquid ntirogen. Storage in the vapour phase liquid nitrogen container for nine months followed by rapid thawing resulted in approximately 10% haemolysis of the red cells. The ability of the thawed red cells to haemagglutinate viruses was unimpaired by the manipulations.