Microaggregates in frozen and saline washed red blood cells.

The microaggregates which accumulate in stored blood have been implicated in the development of posttraumatic pulmonary insufficiency. These particles are known to be composed of degenerated leukocytes and platelets. Because frozen and saline washed red blood cells contain small numbers of leukocytes and platelets, they were studied as a possible source of microaggregate-free red blood cells. Using a Model T Coulter Counter to quantitate all particles 13-80 microns in size, it was shown that freezing and deglycerolization, or simple saline washing (manual or automated), could reduce the number of microaggregates in stored blood by 80 to 90 per cent. These findings add to a growing list of potential advantages in the routine use of frozen red cells for patients requiring transfusion.