Ultrasart D 20 is a disposable ultrafiltration unit containing a cellulose triacetate ultrafilter of 20.000 MWCO. It is supplied individually packed, sterile and pyrogen-free. Ultrasart D 20 is used for removal of substances interfering with LAL test from liquid samples by ultrafiltration. Endotoxin retention is > 99%. Ultrasart D 20 units are used together with a three-place manifold, which is connected to a pressure source via a pressure tank that contains depyrogenated rinsing solution for washing of the concentrated samples inside the Ultrasart D 20 unit. An aliquot of the washed concentrate containing collected endotoxins is used for the LAL test. All hardware components of the Ultrasart sytem can be thermally depyrogenated.