Blood cell filtration test at low flow rates for clinical applications

Abstract

A nuclepore filtration technique was developed for a clinical evaluation of the deformability of blood cells (red and white) at low shear rates. The filtration process of blood suspensions at low pressure differences was recorded continuously with a microscope-TV-video system. The time course of decreasing filtration pressure was analyzed from the video-monitor. The obtained results are as follows: 1) The relative resistance (R_r) of the blood suspension increased in the time course of filtration. 2) When negative pressure was added, the R_r remained almost constant and its increasing rate was very slight. 3) A great difference appeared in the R_r between normal subjects and patients a low pressure difference below around 10 mmH₂O. The R_r showed a difference before and after treating patients. 4) More than 10% WBCs could pass through the nuclepore (5µm diameter). The present nuclepore filtration method showed that the differentiation of RBC deformability at low flow rates was more obvious and sensitive, suggesting it would be useful for clinical applications.