Abstract: A venous refill testing system includes a sensor for sensing patient blood volume at a testing location along a patient's leg during and after dorsiflexion of the patient's foot, and a controller unit having means for automatically determining a time of cessation of dorsiflexion of the patient's foot and for automatically evaluating whether a venous refill time following the time of cessation of dorsiflexion of the patient's foot is less than approximately twenty seconds. The sensor is operably connected to the controller unit, and the controller unit can be actuated to initiate sensing of patient blood volume with the sensor.