Adherence of blood cells to dialyzer membranes as a measure of biocompatibility

Cell adherence to plate dialyzer membranes was analyzed at the end of 4 hours of dialysis. Three types of membranes were examined: Cuprophan Hemophan and Gambrane, (a polycarbonate membrane). The membranes were mounted in dialyzers that contained 23 layers of one membrane type and one layer of each of the two other. Less leukocytes adhered to the Pc than to the Cu and He membranes. Transient initial complement activation during dialysis, which was considerably lower with dialysers containing mainly Pc membrane, was not correlated to adherence of cells to the membranes. Instead flow geometry is proposed as the main factor determining the adherence. Contrary to what has been earlier suggested, we think that leukocyte adherence is not a very suitable measure of membrane biocompatibility. The reason is that the influence of membrane surface-chemical factors can not be separated from mechanical factors due to the design of the device.