A sterile device designed to protect a haemodialysis system pressure monitor and to help maintain the sterility of the blood tubing fluid pathway. It is typically attached between the blood tubing set and the pressure monitor and typically consists of plastic housing that contains a hydrophobic filter with a reference pore size (e.g., 1 to 2 microns) that helps prevent cross-contamination by viruses, bacteria, and particulate matter while preventing the flow of fluids to the pressure monitor. This is a single-use device.