Current Problems and Results in Testing Microaggregate Filters

Most in vitro studies on microaggregate filters focus on the mechanical retention of microparticles. Data are based on bulk techniques such as differential dry weight and screen filtration pressure measurements or single-particle counting using resistance measurement (Coulter principle). Errors in measurements may result from various steps in sample handling, interaction of the sample with the environment and inborn errors of different techniques. High-speed laser cytometry has been applied and was found to diminish the number of possible errors. The results of these measurements are compared with conventional techniques.