[Microfilters and blood transfusion]

The use of microfilters for the transfusion of fresh blood and bank blood stored for 10 and 18 days is reported. No amorphous debris are found in the microfilter after perfusion of fresh blood. After perfusion of blood stored for 10 and 18 days, in two cases aggregates of platelets are found, amorphous debris, however, only in one case in the smallest mesh. On the other hand, in the 300 mu standard filter a passage of amorphous debris through the filter is often to be seen. It is possible that some manipulation has favoured this.