A blood sequestration device configured to isolate an initial, potentially contaminated portion of blood from the flow of blood of a patient, prior to directing the flow of blood to an outlet port where the blood can be accessed. The blood sequestration device including a body member having an interior wall defining a fluid conduit having a distal portion, a first proximal portion, and a second proximal portion, wherein the first proximal portion defines a sequestration chamber configured to isolate an initial portion of blood of a flow of blood, a vent path configured to enable the escape of gas initially trapped within the sequestration chamber.