Efficiency of Superfine Glass Fiber Membrane\= Filters for Depleting Leukocytes

Leukocyteremovalfilters made of superfine glass fiber membranes for depleting leukocytes in red cell suspensions to prevent nonhemolytic transfusion reactions were investigated. The performance evaluation of such filters was based on the detection of leukocyte depletion rate and red cell recovery rate. Residual leukocytes after filtration were counted in a 50 l Nageotte counting chamber. The chemical stability of the glass fiber membranes was studied by plasma emission spectrometer and by measuring the ion content and weighing nonvolatile matter in water extract. The structural stability of the glass fiber membranes was studied by micropore filter membrane method. The results showed that glass fiber membrane filters could deplete more than 99.0% of leukocytes in the red cell suspension prepared from 400 ml whole blood. The total number of residual leukocytes was less than 510\ 6. The water extract of the glass fiber membranes contained only few Si\ \{4 \} and Ca\ \{2 \} and less than 2 mg/100 ml o f nonvolatile matter. No broken or loose fibers were found in the filters. Scanning electron microscopy (SEM) showed that the structure of the glass fiber membranes was instrumental in holding and trapping leukocytes.