An apparatus for detecting Deep Vein Thrombosis (DVT) in a patient includes a computer based device, a device disposed on a predetermined position on a calf of the patient for measuring blood volume, another device for measuring temperature of the calf and still another device for measuring calf size. A cuff is operably connected to the computer based device and envelops a portion of a thigh of the patient and is controllably restrictable by the computer based device to produce a controlled venous occlusion of the patient's deep veins for a predetermined period. A method for detecting DVT using the device is also provided.