Comparison of four blood filtration techniques

Abstract

A constant pressure head (200 Pa) technique is described for measuring blood filtration rate at 23 µl intervals using optical detection of the liquid meniscus. Results obtained in 11 controls and 15 vascular disease patients were compared with the results using three established methods (Hemorheometre, whole blood filtration, and filtration of buffy coat depleted cells in prefi1tered plasma). The comparison of the four techniques showed, that although each was sensitive to different factors, they detected similar differences between controls and vascular disease patients, suggesting complex changes in the properties of the blood, including red cell deformability.

Experiments using the new method suggested a time and pressure dependent reversible clogging-unclogging process during filtration, which was a significant determinant of the filtration rate even at low leucocyte concentrations (0.1 × 10⁹/l) and low filtered volumes (100 µl).