A fluid collection canister including a chamber to collect fluids and a canister top disposed over the chamber. The canister top includes a bottom side facing into the chamber, including first and second ribs disposed thereon, a filter membrane attached to the first and second ribs, a first port to communicate with the chamber and a pressure source external to the chamber, and a second port to communicate with the chamber and a sensor external to the chamber. The first port is in fluid communication with a first area, which is bounded by the filter membrane, the first and second ribs and the bottom side of the canister top. The second port is in fluid communication with a second area, which is bounded by the filter membrane, the second rib and the bottom side of the canister top.
