Plasma separation with a microporous membrane

A plasma separation device is disclosed. The device comprises a filter having an upstream surface and a downstream surface and comprising a microporous membrane, and a housing having an inlet, a downstream chamber, an outlet and at least one air channel, where the filter is disposed in the housing in the fluid flow path, and where the outlet and the air channel are spaced apart and are arranged such that air passes into the downstream chamber via the air channel and sweeps plasma from the downstream surface of the filter and through the outlet, when a negative pressure is created in the downstream chamber. Furthermore, a method of separating plasma from biological fluid using said plasma separation device is disclosed, comprising the steps of applying biological fluid to the filter's upstream surface, passing plasma through the filter, creating a negative pressure in the downstream chamber through the outlet, passing air through the air channel into the downstream chamber and sweeping plasma from the downstream surface of the filter, and passing swept plasma through the outlet.