Bedside filtration: How can we assess its quality?

In order to improve the process control of bedside filtration, a multisampl ing procedure was evaluated. Serial samples of postfiltration blood were co llected, and white blood cells (WBCs) were counted by a microdroplet fluo-r ochromatic assay. The kinetics of the bedside filter efficiency was shown t o be nonlinear, with a saturation-like pattern owing to leukocyte escaping mostly during the second half of the filtration procedure. Multisample proc edure allows the computation of the actual amount of filter-escaping leukoc ytes, while evaluation of filter-escaping leukocytes computed on the basis of a single-point sample (postfiltration terminal segment) may give mislead ing results and an overestimation of the number of filter-escaping WBCs.