A study of the efficiency of four blood microfilters.

A new blood microfilter, Swank 6000-4, was compared with three established blood microfilters, Pall SQ40S, Fenwal 4C2423 and Intercept HR 18137-00 (1321). The flow rate decreased with increasing volume of filtered blood with all the microfilters (p less than 0.01). When the flow rates through each type of microfilter were compared there was no significant difference between them. Screen filtration pressure was restored to normal by the Swank, Fenwal and Intercept microfilters, but remained higher after filtration through the Pall microfilter (p less than 0.01). There was no evidence of red cell loss or damage with any of the microfilters after filtration.