A filter system (100), comprising an elongate filter body (102) defining a lumen and having a proximal end and a distal end. A valve (104) is provided defining a lumen and having a reversibly sealable opening (116) for unidirectional flow of a fluid through the lumen. The valve can be adjoined proximal the distal end of the elongate filter body, wherein the elongate filter body filters the unidirectional flow of the fluid passing through the lumen of the valve and the lumen of the elongate filter body.