A syringe-based device for parenterally-procuring bodily fluid samples with reduced contamination from a patient, the device comprising: a housing including a proximal end portion and a distal end portion and defining an inner volume therebetween, the proximal end portion being substantially open and the distal end portion having a port configured to be coupled to a lumen-defining device for receiving bodily fluid from the patient; a pre-sample reservoir fluidically coupleable to the port and configured to receive and isolate a first volume of bodily fluid withdrawn from the patient; and an actuator mechanism at least partially disposed in the inner volume of the housing, the actuator mechanism having a proximal end portion and a distal end portion, the distal end portion including a sealing member and the proximal end portion including an engagement portion configured to allow a user to selectively move the actuator mechanism, the sealing member defining a channel extending from a distal end to a proximal end of the sealing member, the actuator mechanism configured to move between a first configuration in which the bodily fluid can flow from the port to the pre-sample reservoir through the channel in the sealing member, and a second configuration in which the bodily fluid can flow from the port to a sample reservoir, the sample reservoir defined at least in part by the sealing member and the housing; and at least one mechanical stop configured to prevent removal of the actuator mechanism from the housing; wherein the actuator mechanism includes a first member and a second member, the first member having a proximal end portion and a distal end portion and defining an inner volume therebetween, and the second member having a proximal end portion and distal end portion, the second member movably disposed in the inner volume of the first member thereby defining the pre-sample reservoir in a distal portion of the inner volume of the first member; and a proximal end of the first member includes a protrusion configured to selectively engage a protrusion at the proximal end portion of the second member to substantially limit a proximal movement of the second member relative to the first member. a housing including a proximal end portion and a distal end portion and defining an inner volume therebetween, the proximal end portion being substantially open and the distal end portion having a port configured to be coupled to a lumen-defining device for receiving bodily fluid from the patient; a pre-sample reservoir fluidically coupleable to the port and configured to receive and isolate a first volume of bodily fluid withdrawn from the patient; and an actuator mechanism at least partially disposed in the inner volume of the housing, the actuator mechanism having a proximal end portion and a distal end portion, the distal end portion including a sealing member and the proximal end portion including an engagement portion configured to allow a user to selectively move the actuator mechanism, the sealing member defining a channel extending from a distal end to a proximal end of the sealing member, the actuator mechanism configured to move between a first configuration in which the bodily fluid can flow from the port to the pre-sample reservoir through the channel in the sealing member, and a second configuration in which the bodily fluid can flow from the port to a sample reservoir, the sample reservoir defined at least in part by the sealing member and the housing; and