Abstract: A two-piece body high pressure membrane test cell is disclosed with a tangential feed into the interior pressure chamber in which a central distributor element is mounted with the lower frusto-conical end thereof at a critical spacing above a filter membrane. The membrane is supported on an annular land of a filter support disc which has a peripheral edge zone compressed in a sealed fit between the lower and upper pieces of the cell body. The edge zone is machined to a precise thickness to provide a reproducible and accurate spacing between the filter membrane that rests on the support and the lower end of the distributor.