EVALUATION OF RED-BLOOD-CELL FILTERABILITY TEST - INFLUENCES OF PORE-SIZE, HEMATOCRIT LEVEL, AND FLOW-RATE

  • 1 January 1984
    • journal article
    • research article
    • Vol. 104  (4) , 501-516
Abstract
Suspensions of washed [human] red blood cells in Ringer''s solution with hematocrit values of 5%, 10% and 15% were pumped at flow rates of 0.42 and 0.82 ml/min through polycarbonate filters with pore sizes of 2.6 .+-. 0.2, 4.5 .+-. 0.6, and 6.9 .+-. 0.8 .mu.m (mean .+-. SD). The initial pressure generated at the filter was normalized for pressure reading obtained with cell-free Ringer''s solution at the same flow rate and used for the calculation of the relative resistance of 1 red blood cell in a pore. This measurement was independent of the flow rate and the hematocrit level, but it varied inversely with the pore size: 175.1 .+-. 62.5, 5.2 .+-. 1.2 and 2.4 .+-. 0.8 for the 2.6, 4.5, and 6.9 .mu.m pores, respectively. Plugging of filter pores as evidenced by progressive pressure rise at constant flow was a prominent feature for 2.6 .mu.m filters, but was not significant for 6.9 .mu.m filters. At the flow rates studied, < 1% of the filtered red blood cells showed morphologic changes or underwent hemolysis. The 2.6 .mu.m filters are most sensitive in detecting altered red blood cell filterability induced in vitro and occurring in vivo. These results may help to define an optimum filtration test for clinical investigations.