[Microaggregate formation in buffycoat-free packed red cells (author's transl)]

The amounts of microaggregates of 200 non-selected units of buffycoat-free PRC were determined gravimetrically using a cascade of nylon mesh screen filters with pore sizes of 200, 50, 20 and 10 micrometers. In PRC the total amounts of amorphous debris are on average 2 to 3 times less than in stored whole blood. Nevertheless the quality of the buffycoat-free PRC is subject to immense variation in view of removed debris in individual cases. Microaggregates retained on the 20 and 10 micrometer filter sieves are still considerable, their order of magnitude is comparable to that found on the 200 micrometer sieves, so that a microfiltration is also necessary under 40 micrometers. Taking into account the necessity of eliminating all factors which contribute to the cause or severity of an acute pulmonary failure even buffycoat-free PRC should be transfused through microfilters.